Matt Glassman has a very interesting and useful post today about the complexity of counting filibusters. He's quite right that the charts you've all seen that count cloture votes aren't quite as accurate as one might think. It's very possible that some of those cloture votes overcount filibusters (because the majority might prefer for tactical reasons to use cloture to get to a vote rather than some other procedure) and certainly undercount filibusters (because the majority may not bother to seek cloture when it knows it doesn't have the votes). If you're really interested in filibustering, you should click over there.
However, I think that there's a bottom line here that's easy to overlook: the institutionalization of the 60 vote Senate. It's not really a question, in other words, of whether any particular piece of legislation or nomination was attacked by filibuster; it's that increasingly beginning in 1993, and overwhelmingly since 2009, minority parties have insisted that the majority produces 60 votes for everything.
I wrote about this over at Plum Line earlier today: it just isn't the case that it always took a cloture-sized majority to pass things. Remember that Clarence Thomas was confirmed for the Supreme Court in a 52-48 vote. That's 1991, everyone. In 2011, no one gets confirmed on a 52-48 vote. No legislation gets approved on a 52-48 vote (barring procedural protections such as reconciliation). I used to think that perhaps, on legislation at least, we might have a problem knowing about invisible filibusters in the past that prevented the majority from even beginning to act, but Greg Koger pretty much shot that down.
No, the 60 vote Senate is the key evidence here...or, I guess I should say, how rare passage is of anything by fewer votes than needed for cloture. Of course, there are all sorts of reasons that things might pass with more than 60 votes. And it's also the case that a sub-60 vote doesn't mean that there was no filibuster along the way that was defeated by attrition or resolved by compromise. But a Senate that has no or very few sub-60 winning votes is a Senate with universal filibustering. At that point, counting individual filibusters is pointless; the entire process is immersed in filibuster. And that's where we are now -- but it wasn't always the case.