I went fulltime in 2005, so I'll start there (ratios are by uniques):
2005 1:148
2006 1:353
2007 1:465
2008 1:513
2009 1:260
2010 1:1448
2011 1:2924
2012 1:3081
this year so far is 1:1674 but that's on less than 1m uniques, whereas the previous years (except 2005) are all obviously more than that.
tidbit - 2009 I had 1/6th the traffic of 2011, but +3x the income
