中國兩千多年來的人口成長曲線圖( 資料來自美國哥倫比亞大學網站:其中曲線的厚度代表估計的誤差值 ):
http://afe.easia.columbia.edu/special/china_1950_population.htm
"Between 1851 and 1949, a century of rebellion, social upheaval, and suffering, China's population base increased "only" by another 100,000,000(晚清到民國結束的一百年期間,人口僅從原來的四億三兩百萬人增加了一億左右) on top of its 432,000,000 base. (During the same period, the population of the United States increased from about 23,000,000 to 151,000,000. Of this 128 million increase in the US, 36 million was due to immigration.同一時期的美國人口則增加了六點五倍:由當時2300萬人增加了一億兩千八百萬人至一億五千一百萬人,) While China's absolute increase over this century was far below the increases of the preceding several centuries, the magnitude of China's overall population nonetheless bequeathed to the newly established People's Republic of China a resource of great potential and challenge of immense proportions."
為何從1851~1949年晚清至民國結束的一百年期間,中國人口僅僅增加了一億左右(幾乎呈現了停滯現象),除了饑荒營養不良與戰禍外,抽鴉片煙,逛八大胡同嫖妓等等傳染病源衛生條件及習慣不良,上至王公貴族,下到販夫走卒,莫名其妙皆以吸食鴉片為尊榮,所造成人均期壽命不到四十歲,也是最主要的原因!
老共在1949~1956年開始不斷的發起"送瘟神"等清潔衛生運動,並嚴禁抽鴉片嫖妓等等中國人的"寡人有疾",澈底改變整體中國人衛生習慣,與提升中國人均期壽命到六十五歲,是造成1949年後中國人口迅速增長的原因之一。朝鮮戰爭讓外國不敢再侵略中國,也是另外一個重要原因!