出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/01/16 14:07:34」(JST)
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The birth rate (technically, births/population rate) is the total number of live births per 1,000 of a population in a year.[1] The rate of births in a population is calculated in several ways: live births from a universal registration system for births, deaths, and marriages; population counts from a census, and estimation through specialized demographic techniques. The birth rate (along with mortality and migration rate) are used to calculate population growth.
The crude birth rate is the number of live births per 1,000 people per year.[2] Another term used interchangeably with birth rate is natality.[3] When the crude death rate is subtracted from the crude birth rate, the result is the rate of natural increase (RNI).[4] This is equal to the rate of population change (excluding migration).[4]
The total (crude) birth rate (which includes all births)—typically indicated as births per 1,000 population—is distinguished from an age-specific rate (the number of births per 1,000 persons in an age group).[5] The first known use of the term "birth rate" in English occurred in 1859.[6]
| Years | CBR | Years | CBR |
|---|---|---|---|
| 1950–1955 | 37.2 | 2000–2005 | 21.2 |
| 1955–1960 | 35.3 | 2005–2010 | 20.3 |
| 1960–1965 | 34.9 | 2010–2015 | 19.4 |
| 1965–1970 | 33.4 | 2015–2020 | 18.2 |
| 1970–1975 | 30.8 | 2020–2025 | 16.9 |
| 1975–1980 | 28.4 | 2025–2030 | 15.8 |
| 1980–1985 | 27.9 | 2030–2035 | 15.0 |
| 1985–1990 | 27.3 | 2035–2040 | 14.5 |
| 1990–1995 | 24.7 | 2040–2045 | 14.0 |
| 1995–2000 | 22.5 | 2045–2050 | 13.4 |
In 2012 the average global birth rate was 19.15 births per 1,000 total population,[8] compared to 20.09 per 1,000 total population in 2007.[9]
The raw birth rate (not births/population rate) is 4.3 births/second for the world (2014 est.).[10]
The birth rate is an issue of concern and policy for national governments. Some (including those of Italy and Malaysia) seek to increase the birth rate with financial incentives or provision of support services to new mothers. Conversely, other countries have policies to reduce the birth rate (for example, China's one-child policy). Policies to increase the crude birth rate are known as pro-natalist policies, and policies to reduce the crude birth rate are known as anti-natalist policies. Measures such as improved information on birth control and its availability have achieved similar results in countries such as Iran.
There has also been discussion on whether bringing women into the forefront of development initiatives will lead to a decline in birth rates. In some countries, government policies have focused on reducing birth rates by improving women's rights, sexual and reproductive health. Typically, high birth rates are associated with health problems, low life expectancy, low living standards, low social status for women and low educational levels. Demographic transition theory postulates that as a country undergoes economic development and social change its population growth declines, with birth rates serving as an indicator.
At the 1974 World Population Conference in Bucharest, Romania, women's issues gained considerable attention. Family programs were discussed, and 137 countries drafted a World Population Plan of Action. As part of the discussion, many countries accepted modern birth control methods such as the birth control pill and the condom while opposing abortion.[citation needed] In 1994, another action plan was drafted in Cairo, Egypt, under the aegis of the United Nations. Population and the need to incorporate women into the discourse were discussed; it was agreed that improvements in women's status and initiatives in defense of reproductive health and freedom, the environment, and sustainable socioeconomic development were needed.
Birth rates ranging from 10–20 births per 1,000 are considered low, while rates from 40–50 births per 1,000 are considered high.[citation needed] There are problems associated with both extremes. High birth rates may stress government welfare and family programs. Additional problems faced by a country with a high birth rate include educating a growing number of children, creating jobs for these children when they enter the workforce, and dealing with the environmental impact of a large population. Low birth rates may stress the government to provide adequate senior welfare systems and stress families who must support the elders themselves. There will be fewer children (and a working-age population) to support an aging population.
According to the CIA's The World Factbook, the country with the highest birth rate is Niger (at 51.26 births per 1,000 people). The country with the lowest birth rate is Monaco, at 6.72 births per thousand.
Compared with the 1950s (when the birth rate was 36 per thousand),[11] the birth rate has declined by 16 per thousand. In July 2011, the U.S. National Institutes of Health announced that the adolescent birth rate continues to decline.[12]
Birth rates vary within a geographic area. In Europe as of July 2011, Ireland's birth rate is 16.5 per 1000 (3.5 percent higher than the next-ranked country, the UK). France has a birth rate of 12.8 per thousand, while Sweden is at 12.3.[13][14]
In July 2011, the UK's Office for National Statistics (ONS) announced a 2.4 percent increase in live births in the UK in 2010.[15] This is the highest birth rate in the UK in 40 years.[15] However, the UK record year for births and birth rate remains 1920 (when the ONS reported over 957,000 births to a population of "around 40 million").[16] In contrast, the birth rate in Germany is only 8.3 per thousand—so low that the UK and France (which have smaller populations) had more births in the past year.[17]
Birth rates also vary in a geographic area among demographic groups. For example, in April 2011 the U.S. Centers for Disease Control and Prevention announced that the birth rate for women over age 40 in the U.S. rose between 2007 and 2009 and fell in every other age group during the same period.[18]
In August 2011 Taiwan's government announced that its birth rate declined in the previous year, despite the fact that the government implemented approaches to encourage fertility.[19]
According to U.S. federal-government data released in March 2011, births fell four percent from 2007 to 2009 (the largest drop in the U.S. for any two-year period since the 1970s).[20] Births have declined for three consecutive years, and are now seven percent below the 2007 peak.[21] This drop has continued through 2010, according to data released by the U.S. National Center for Health Statistics in June 2011.[22] Experts have suggested that this decline is a reflection of unfavorable economic conditions.[23] The connection between birth rate and economic conditions stems from the fact that US birth rates have fallen to levels comparable to those during the Great Depression during the 1930s.[24] A state-level look at fertility, based on a report published by the Pew Research Center in October 2011, points out the strong correlation between lower birth rates and economic distress. In 2008, North Dakota had the nation’s lowest unemployment rate (3.1 percent) and was the only state to show an increase (0.7 percent) in its birth rate. All other states either remained the same or declined.
The research center’s study also found evidence of a correlation between economic difficulties and fertility decline by race and ethnicity. Hispanics (particularly affected by the recession) have experienced the largest fertility decline, particularly compared to Caucasians (who have less economic hardship and a smaller decline in fertility). In 2008–2009 the birth rate declined 5.9 percent for Hispanic women, 2.4 percent for African American women and 1.6 percent for white women. This may be associated with the fact that Hispanics have suffered the most loss of wealth[citation needed] since the beginning of the recession, and have a high unemployment rate[according to whom?]
Other factors (such as women’s labor-force participation, contraceptive technology and public policy) make it difficult to determine how much economic change affect fertility. Research suggests that much of the fertility decline during an economic downturn is a postponement of childbearing, not a decision to have fewer (or no) children; people plan to “catch up” to their plans of bearing children when economic conditions improve. Younger women are more likely than older women to postpone pregnancy due to economic factors, since they have more years of fertility remaining.[25]
In 2013, teenage birth rates in the U.S. were at the lowest level in U.S. history.[26] Teen birth rates in the U.S. have decreased from 1991 through 2012 (except for an increase from 2005–2007).[26] The other aberration from this otherwise-steady decline in teen birth rates is the six percent decrease in birth rates for 15- to 19-year-olds between 2008 and 2009.[26] Despite the decrease, U.S. teen birth rates remain higher than those in other developed nations.[26] Racial differences affect teen birth and pregnancy rates; American Indian/Alaska Native, Hispanic, and non-Hispanic black teen pregnancy rates are more than double the non-Hispanic white teenage birth rate.[27]
The United States population growth is at an historical low level as the United States current birth rates are the lowest ever recorded.[28] The low birth rates in the contemporary United States can possibly be ascribed to the recession, which led women to postpone having children and fewer immigrants coming to the US. The current US birth rates are not high enough to maintain the size of the U.S. population, according to The Economist.[29][30]
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| リンク元 | 「natality」「出生率」「birthrate」 |
| 関連記事 | 「rate」「rat」「birth」 |