Globally the average fertility rate (the number of children a woman can expect during her lifetime) has roughly halved in the past half century, from five in the mid-1950s to 2.5.

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They knew that China's fertility rate, or the average number of children born to each woman, was in decline even before the one-child policy began in 1980.

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At the same time, the fertility rate (the number of children an average woman will have in a lifetime) is now 1.39, well below the replacement level.

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