When you start looking at large numbers of old records, you begin to see a pattern of first names. Many names are used again and again in a single family. Other names, such as Hezekiah, may have been popular at one time but not today. Many babies are named after popular figures of the time, such as George Washington Smith or Lorenzo Dow Jones.
Did you ever wonder what were the most popular names for baby boys and girls in the early 1900s? Or how about of modern times? The U.S. Social Security Administration provides table after table of popularity rankings by decade, by state, and (starting in 1990) by year. Data is based on a 5% sampling of social security card applications.
You can check the popularity of your own first name at http://www.SSA.gov/OACT/babynames