In these decades prior to 2000, Glen Canyon Dam frequently released more than the required to Lake Mead each year. This allowed Lake Mead to maintain a high water level despite releasing significantly more water than it is contracted for. However, since 2000, the Colorado River has experienced persistent drought, with average or above-average conditions occurring in only five years (2005, 2008–2009, 2011 and 2014) in the first 16 years of the 21st century. Although Glen Canyon was able to meet its required minimum release until 2014, the water level in Lake Mead has steadily declined. The decreasing water level is due to the loss of the surplus water that once made up for the annual overdraft.