I'm confident that this fact plays a role in the dips: > The rate of caesarean section births in the U.S. was 32.7 percent in 2013 With so many c-sections bei

I'm confident that this fact plays a role in the dips: > The rate of caesarean section births in the U.S. was 32.7 percent in 2013 With so many c-sections being performed there is more selection of birthdates.