When asked about the new data, Barham Salih, an Iraqi deputy prime minister, said in an interview that the troop increase was having a positive impact in specific neighborhoods in Baghdad, particularly in the Shiite-dominated eastern half of the city. But he said Iraqi intelligence had concluded that Al Qaeda was in effect surging at the same time in Iraq to counteract the American program, damping any immediate gains.

Mr. Salih also said that insurgents had to some extent fled Baghdad, where the increase is concentrated, to outlying areas like the northern cities of Mosul and Kirkuk, the Kurdish north and the ethnically mixed province of Diyala, north and west of Baghdad, where major attacks have taken place in recent weeks.

“Al Qaeda has adapted, first by pushing a surge of its own, and by escalation of its own attacks across Iraq,” Mr. Salih said. “It is a deliberate attempt by Al Qaeda, an escalation, to get us to change our tactics.”

Over all, the attack statistics, which the accountability office has been compiling since the early days of the conflict, paint a sobering picture of where the country is headed. The number of daily attacks remained low through 2003 and the early months of 2004, but then began a relentless climb even as the United States promoted what it saw as important political milestones in Iraq.

Image On April 2, a suicide bomber blew up a truck near a school in Kirkuk, wounding dozens of children. The daily attack figure for April was 149. Credit... Marwan Ibrahim/Agence France-Presse — Getty Images

Those milestones included the transfer of the country to a sovereign Iraqi government, several elections and eventually the creation and ratification of a new Iraqi Constitution. Despite those developments, the statistics show, the number of attacks averaged 71 a day in January 2006, and rose to a record high of 176 a day in October 2006.