Nearly all attempts at the summit are done using one of the two main routes. The traffic seen by each route varies from year to year. In 2005-07, more than half of all climbers elected to use the more challenging, but cheaper northeast route. In 2008, the northeast route was closed by the Chinese government for the entire climbing season, and the only people able to reach the summit from the north that year were athletes responsible for carrying the Olympic torch for the 2008 Summer Olympics. The route was closed to foreigners once again in 2009 in the run-up to the 50th anniversary of the Dalai Lama's exile. These closures led to declining interest in the north route, and, in 2010, two-thirds of the climbers reached the summit from the south.