estimates from the sources cited above are used, the ratio was around 1:1. According to military historian and Israeli Ambassador to the United States Michael Oren, for every Serbian soldier killed by NATO in 1999 (the period in which Operation Allied Force took place), four civilians died, a civilian to combatant casualty ratio of 4:1. Oren cites this figure as evidence that "even the most moral army can make mistakes, especially in dense urban warfare". Afghanistan War According to the Watson Institute for International and Public Affairs at Brown University, as of January 2015 roughly 92,000 people had been killed in the Afghanistan war, of which over 26,000 were civilians, for a civilian to combatant ratio of 0.4:1. Iraq War According to a 2010 assessment by John Sloboda of Iraq Body Count, a United Kingdom-based organization, American and Coalition forces had killed at least 28,736 combatants as well as 13,807 civilians in the Iraq War, indicating a civilian to combatant casualty ratio inflicted by coalition forces of 1:2. However, overall, figures by the Iraq Body Count from 20 March 2003 to 14 March 2013 indicate that of 174,000 casualties only 39,900 were combatants, resulting in a civilian casualty rate of 77%. US drone strikes in Pakistan The civilian casualty ratio for U.S. drone strikes in Pakistan is notoriously difficult to quantify. The U.S. itself puts the number of civilians killed from drone strikes in the last two years at no more than 20 to 30, a total that is far too low according to a spokesman for the NGO CIVIC. At the other extreme, Daniel L. Byman of the Brookings Institution suggests that drone strikes may kill "10 or so civilians" for every militant killed, which would represent a civilian to combatant casualty ratio of 10:1. Byman argues that civilian killings constitute a humanitarian tragedy and create dangerous political problems, including damage to the legitimacy of the Pakistani government and alienation of the Pakistani populace from America. An ongoing study by the New America Foundation finds non-militant casualty rates started high but have declined steeply over time, from about 60% (3 out of 5) in 2004–2007 to less than 2% (1 out of 50) in 2012. The study puts the overall non-militant casualty rate since 2004 at 15–16%, or a 1:5 ratio, out of a total of between 1,908 and 3,225 people killed in Pakistan by drone strikes since 2004.