Just looking at NRMP match table (
http://www.nrmp.org/wp-content/uploads/2015/03/ADT2015_final.pdf), page 1, bottom of table:
Total Positions 27,293
US Seniors 25,931
Total Applicants 52,860
Granted, I'm post call, and it's near midnight where I am, but suuuuure looks like we're pretty close with the US Seniors and Total PGY-1 positions available. I assume US Seniors includes DO applicants, but there's a lot of DO schools coming online in the next few years. In 2016 there's 6000 projected DO grads, up 1500 from 2014 (when I last looked at the data). That's pretty dang close to 1:1 for available PGY-1 positions and US Seniors applying for spots.