Many folks applied for USA passports in 2006 due to new requirements. There is also a surge in new applications ahead of the 2018 Real ID Act requirements so fast forward to 2016 and guess what? That flood of new passports in 2006 are expiring and a bunch of new applications is making it a busy time at the U.S. Passport office.  They are urging individuals with passports expiring to renew them now. Renewals will likely take 6 weeks or more.  Also if you are planning travel out of the country remember that you typically need at least 6 months of validity on your passport before you are allowed to travel to most places.

Here is link for more information: https://travel.state.gov/content/passports/en/passports/information/where-to-apply/agencies.html