The year 2005 is the midpoint of a decade that spans three unique, important transition in the history of humankind. 【S1】______ Before 2000, young people always outnumber old people. 【S2】______ From 2000 forward, old people will outnumber young people. Until approximately 2007, rural people will have always been outnumbered urban people. From approximately 【S3】______ 2007 forward, urban people will not outnumber rural people. From 2003 on, the median woman worldwide have had, and will continue to have, too few or just enough children during her lifetime to replace themselves and the father in 【S4】______ the following generation. The century with 2000 as its midpoint marks three additional unique, important transitions in human history. First, any person who died before 1930 had lived through 【S5】______ a doubling of the human population. Nor is any person born in 2050 or later likely to live through a doubling of the human population. On contrast, everyone 45 years old 【S6】______ or elder today has seen more than a doubling of human 【S7】______ numbers from three billion in 1960 to 6.5 billion in 2005. The peak population growth rate ever reached about 2.1 percent a year, that occurred between 1965 and 1970. Human 【S8】______ population never grew with such the speed before the 20th 【S9】______ century and is never again likely to grow with such speed. Our descendants will look back on the late 1960s peak like 【S10】______ the most significant demographic event in the history of the human population even though those of us who lived through it did not recognize it. 【S1】