The weekly average price of the Organization of Petroleum Exporting Countries (OPEC) kept dropping last week, falling to 100.61 U.S. dollars a barrel, said the Vienna-based cartel Monday. OPEC oil price has been dropping for five consecutive weeks, decreasing by 9.51 dollars, or 8.6 percent. During last week, OPEC oil price fell to its lowest level since Feb. 14 this year, reaching 98.59 dollars a barrel. But it then rebounded for three consecutive days and reached 103.22 dollars a barrel on last Friday. The debt crisis in Europe as well as the bleak U.S. economic outlook remained as the key factors affecting the international oil prices last week. Early last week, due to the further exacerbated U.S. economic outlook, not only the global crude oil prices but also the prices of the precious metals silver, copper and platinum dived. However, the encouraging U.S. employment figures published lately, along with the signs that European leaders began taking proactive measures to deal with the debt crisis drove the prices later in the week. Analysts believed that the two factors would help stabilize the global oil price and stop its downward trend.