for food, wait in lines for hours and sometimes settle without having certain products. Maduro's government has blamed the shortages on "bourgeois criminals" hoarding goods. A drought, combined with a lack of planning and maintenance, has caused a hydroelectricity shortage. To deal with lack of power supply, in April 2016 the Maduro government announced rolling blackouts and reduced the government workweek to only Monday and Tuesday. A multi-university study found that, in 2016 alone, about 75% of Venezuelans lost weight due to hunger, with the average losing about 8.6 kg (19 lbs) due to the lack of food. By late-2016 and into 2017, Venezuelans had to search for food on a daily basis, occasionally resorting to eating wild fruit or garbage, wait in lines for hours and sometimes settle without having certain products. By early 2017, priests began telling Venezuelans to label their garbage so needy individuals could feed on their refuse. In March 2017, Venezuela, with the largest oil reserves in the world, began having shortages of gasoline in some regions with reports that fuel imports had begun. Petroleum and other resources Venezuela has the largest oil reserves, and the eighth largest natural gas reserves in the world. Compared to the preceding year another 40.4% in crude oil reserves were proven in 2010, allowing Venezuela to surpass Saudi Arabia as the country with the largest reserves of this type. The country's main petroleum deposits are located around and beneath Lake Maracaibo, the Gulf of Venezuela (both in Zulia), and in the Orinoco River basin (eastern Venezuela), where the country's largest reserve is located. Besides the largest conventional oil reserves and the second-largest natural gas reserves in the Western Hemisphere, Venezuela has non-conventional oil deposits (extra-heavy crude oil, bitumen and tar sands) approximately equal to the world's reserves of conventional oil. The electricity sector in Venezuela is one of the few to rely primarily on hydropower, and includes the Guri Dam, one of the largest in the world. In the first half of the 20th century, U.S. oil companies were heavily involved in Venezuela, initially interested only in purchasing concessions. In 1943 a new government introduced a 50/50 split in profits between the government and the oil industry. In 1960, with a newly installed democratic government, Hydrocarbons Minister Juan Pablo Pérez Alfonso led the creation of OPEC, the consortium of oil-producing countries aiming to support the price of oil. In