How many diapers are used in the us a year?

The U.S. usues 36 billion disposable diapers annually based on the number of babies born each year (~4.2 million), the fact that most kids wear diapers until the age of 3.5 years, starting at 11 per day and winding down to 5 per day, and assuming 10% of the population uses cloth diapers.