Could the 5% drop be accounted for considering the numbers are for April 14th 2017 and not after the filing deadline of April 18th 2017? Seems like many people would file and/or postmark their returns Monday or Tuesday.
Both dates are 4 days before the tax deadline for the respective years.
Different days of the week, though. That affects behavior a lot.
Tax day in 2016 was also April 18th.
I'm wondering if it had something to do with Easter. There might be a lot of people who were tied up with family stuff and figured they could start on Monday. Last year Easter was in March.
Why not use stats from April 18th then?
Cause IRS devops isn't there yet. They (collect?) release metrics on Fridays.
It is Friday? Roughly 4PM on Friday, which means they'll likely be closing down shortly. Seems odd for them to do it as such a last minute thing.