For example, the average age of the onset of menstrual periods in girls was 15 in 1900. By the 1990s, this average had dropped to 12 and a half years of age.uberty facts. 1  Puberty is the period of sexual maturation and achievement of fertility. 2  The time when puberty begins varies greatly among individuals; however, puberty usually occurs in girls between the ages of 10 and 14 and between the ages of 12 and 16 in boys.
Herbert Hoover was the president of the U.S. when the great depression began in 1929.
FDR Presidential Library & Museum. What was the Great Depression? The Great Depression  was a severe, world -wide economic disintegration symbolized in the United States by the stock market crash on Black Thursday, October 24, 1929 . The causes of the Great Depression were many and varied, but the impact was visible across the country. By the time that FDR was inaugurated president on March 4, 1933, the banking system had collapsed, nearly 25% of the labor force was unemployed, and prices and productivity had fallen to 1/3 of their 1929 levels.