A new peer-reviewed study has concluded that at least 100,000 Iraqi civilians have died because of the U.S invasion last year. The study appears in the British medical journal Lancet and was conducted by researchers at Columbia University, Johns Hopkins and Al-Mustansiriya in Baghdad. The rise in the death rate was mainly due to violence and much of it was caused by U.S. air strikes on towns and cities. The estimated number of deaths is considerably higher than previous estimates. The U.S. military claims it does not keep tallies on civilian casualties. The researchers made its calculation based on door-to-door surveys in Baghdad where they gathered data to determine how the country’s death rate has changed since the U.S. invaded Iraq. Other estimates have put the civilian toll between 16,000 and 35,000.