There might be some seasonal variation playing a role in it.
However, when I compare year over year the period May 1st to May 31, 2013 is down 24% from the same period in 2012
If I compare the same period from 2011 to 2013, then 2013 is down 28%
If I look at the period just after penguin 2 (which struck on May 22nd of 2013) I am down 32% from 2012
If I compare from May 22nd 2013 through June 22nd, 2013 with the same period from 2011, I am down 41%.