Mathematical Modeling Problem: Just How Many Suckers Are There Right Now?

The phrase "There's a sucker born every minute." was allegedly uttered by a famous person during the 19th century. Assuming it was true and estimating the year based on the possible people to whom the phrase has been attributed, and birth and death rates at appropriate times, estimate how many suckers occupied Earth on 1 January 2015. Be sure to state all of your assumptions explicitly and clearly.

Note: Considerations could include, e.g., whether the rate of births resulting in suckers has changed over time, whether somebody who was born a sucker must necessarily remain so, etc.

Extra credit: Derive from physical principles how many licks it takes to get to the Tootsie Roll center of a Tootsie Pop.

If you look at the Wikipedia entry, you'll see that the quote is of unknown origin and that the attribution to P. T. Barnum is apparently almost certainly wrong.