And technically, he's right. This is the first time in more than a quarter century that a divided Congress has agreed on a budget. But if you think about it, that turns out not to be a very impressive statistic, because in the 26 fiscal years between the last time this happened and now, there have been just three opportunities for a divided Congress to pass a budget: Fiscal years 2003, 2011, and 2012, and of those three, 2003 was something of an outlier because it occurred after a rare mid-session change of control of the Senate.
So while Ryan's "since 1986" formulation might sound impressive, a better way of putting it would be to say that after two or three straight failures (depending if you count 2003), a divided Congress has finally agreed on a budget. Obviously, that doesn't really sound all that impressive, especially when you consider the fact that Ryan himself was a big part of the reason that we didn't have a budget agreement because he was chairman of the House Budget Committee during the last two failures.
It's even less impressive if you consider the fact that they only agreed to the budget midway through the third month of the fiscal year—and after Republicans forced the country through a government shutdown. In 1986, the year that Ryan fondly compares his deal to, the House and Senate agreed on a budget in June, more three months before the beginning of the fiscal year.
I know that looking at facts gets a little more wonky and in the weeds than Paul Ryan would like, but despite his clean-cut appearance and earnest presentation style, fiscal policy under his leadership has been an absolute train wreck, no matter how you look at it. The only thing historic about it is how bad it's been.