Thursday, April 2, 2015

Births and Birthdays

I have an interest in demographics and have written about it from time to time in BeeLine.

It is a window to the future that is too often overlooked or ignored.  The long-term trends are often the most difficult to see in the 24 hour news cycle world we live in today.  In this day and age when there is so much focus on the trees (even the leaves at times!), demographics forces you to look at the forest.

I have been tracking U.S. birth rates for a number of years. The birth rate data for 2013 was recently released by the National Vital Statistics System section of the U.S. Department of Health and Human Services.

A few factoids from the report.

  • There were 3,932,181 reported births in the U.S. last year
    • That is 1% lower than in 2012
  • 40.6% of the births were to unmarried women
    • In 1960, only 5.3% of birth were to unwed mothers as shown in the chart below.
    • 71.5% of black babies are born to unwed mothers.


  • There are more babies born to mothers in the age 25-29 age group than any other age cohort
    • However, the birth rate per 1,000 for women 25-29 and 20-24 is the lowest it has ever been in the history of the U.S.
    • The total fertility rate for all women over their lifetimes is 1.85 children. This is below the 2.1 replacement rate necessary to maintain a stable population.
  • Teen births continue to decline.
    • Births to teens are about 1/3 of what they were in 1960.
  • Births of twins are at an all-time high---33.7 per 1,000 births 
  • Six women of age 19 had their 8th child during 2013! (Are you kidding me?)
    • Four white women, two black women
  • 677 women age 50-54 gave birth to a child during the year
    • 221 were first births (Congratulations! However, these mothers will be eligible for Social Security and Medicare when their kids are teenagers. Good luck as well!)

The chart below shows births from 1950 through 2013 in order to give you some better perspective on historical birth rates.  This is a chart that I have been tracking since the early 1990's.  I actually consider the 1965-1986 period to represent the entire "Baby Dearth" period. On either side of the "Baby Dearth" we have the "Baby Boom" (1946-1964) and the "Baby Boomlet" (1987-2010?).  




I have always looked at the birth cohort of 1965-1986 to be particularly well positioned for career prospects in that they are in a great position to be able to serve both a large group of individuals older than themselves (health care, investments, etc) as well as a large population of younger individuals behind them (education, consumer goods etc).  It is a position that is literally in the middle of two giant demographic waves unlike anything we have ever seen before.

Writing about all of this birth info reminded me of one of my favorite charts.

It is this heat map chart that shows how common certain birth dates are that Matt Stiles of The DailyViz put together based on a data on birthdays that was in The New York Times.




A few observations on birth dates based on this data.

  • September has the most birth dates.  September 16 is the most common birthday.  Look at the heavy number of births in September starting with September 8.  Of the top 16 birth dates, 14 of those dates are bunched between September 8 and September 25.
  • December 25 has the fewest births (excluding February 29).  December 24 ranks #363 and December 26 ranks #360.  January 1 is #364.
  • Looking at these numbers you might think not much is going on 9 months before December. However, December 30 is #26, December 29 is #42 and December 28 is #62.  December 31 is #220.
  • January does not have any birth date higher than #260.  In fact, between January 1 and January 11 the rankings are (in order from 1/1)---#364, #362, #356, #350, #338, #301, #324, #347, #351, #349, #341.  Not a good time to be selling birthday cakes.
  • The week around Thanksgiving also has very few birth dates.  From November 22 to November 29 the highest ranking is #340.
  • The low number of birth dates around the Thanksgiving and Christmas holidays suggest that something besides nature is involved.  It would be interesting to look at the C-section rates right before these holidays.  C-sections make up about a third of all births. If it is Friday it is much higher than that suggesting a high number of "elective" C-sections for convenience.  
  • The heaviest birth date months-July, August and September-are nine months after October, November and December proving that the onset of cold weather warms things up in other places.  


By the way, today (April 2) is the most popular birthday in the month of April.


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