James Fallows at The Atlantic posted this graph and comment yesterday (click for larger version):

cloture

Notes Fallows:

The blue line, on the top, is the significant one: it is a gauge of how often bills or nominations were subjected to the need for a “supermajority” vote, rather than a regular Constitutional majority. The goldish line, on the bottom, indicates how often the supermajority prevailed — how often they “broke the filibuster.” As a reminder, there is nothing in the Constitution about this practice. (Supermajorities for certain situations, like impeachment or ratifying treaties or passing Constitutional Amendments, yes; as a general practice, no.)

Easy to see why not much gets done.