Without further ado, the updated graph based on their data:
I usually do the count of coalition deaths in blue and the civilian/security forces count in red. My recent update of the coalition death count reversed that practice accidentally. With this graph the former tradition is re-established.
By way of analysis, the numbers from March (nearly 1,000 deaths counted) offered war opponents and anti-American propagandists some encouragement, to the extent that the numbers trended upward. In terms of the situation on the ground, however, the numbers should not have been discouraging. The Mahdi Army, a Shiite militia nominally under the command of anti-American radical cleric Moqtada al-Sadr, resisted a surprise crackdown initiated by Iraqi PM Nouri al-Maliki. That conflict resulted in a spike in violence while at the same time U.S. forces continued to try to root al Qaeda in Iraq out of its latest (lastest?) safe haven. In other words, the increased casualty numbers reflected the fallout from specific strategic moves that should have been expected to cause a rise in death statistics without indicating a worsening of the situation in Iraq.
Mainstream media sources such as The New York Times generally reported the confrontation between Iraqi security forces and the al-Sadr militia as a setback. That assessment was unreasonable at the time and even more so in retrospect, as al-Maliki has cemented his support across sectarian lines now, largely based on his willingness to confront the Shiite militia.
The rise to nearly 1,000 deaths in March of 2008 probably represents an isolated spike rather than an enduring upward trend.