I wouldn't put to much weight into the graph. It's very possible to work only 75hrs every month or average over 100 hours a month on pay depending different factors.

In 2007 I averaged 105hrs credit a month of pay, blocked 780 hours on the year. This year, with the schedule reductions, only 88 hours of credit a month on average. Even though my hourly rate is $4-5 an hour higher, I made significantly less than 2 years ago.