Here are some charts illustrating these facts based on data from Iraq Coalition Casualities.
Trend for the war's duration:
Here we can see a month by month trend for the first half of 2006 and 2007.
As you can see, there is a decrease in June and the overall pattern mirrors that of last year. We can expect to hear claims of victory in July and Sept claiming that the violence is down as a result of the surge. This is absurd as claiming that the surge is working because it is hot in July, but that is what we will hear.