Awwal 09, 1432, April 13, 2011, SPA -- The number of attacks against aid workers has tripled in the past decade, resulting in the deaths of more than 100 humanitarian workers each year, the United Nations said in a report released on Tuesday. "Due to the dual nature of the U.N. as both a political actor and a humanitarian actor, U.N. aid agencies have more difficulty projecting a neutral image than many other humanitarian agencies," former U.N. aid chief Jan Egeland said at the launch of the report titled, "To Stay and Deliver." More than 90 percent of aid workers are national staff and they bear the brunt of the attacks but international workers have a higher per capital incidence of attack, the report said. United Nations staff face the highest risk of attack followed by Western aid agencies, the report added.