The United States was a critical player in assisting Kazakhstan to get rid of its strategic nuclear weapons stockpile and dismantle its nuclear weapons infrastructure between 1991 and 1996 through the provision of Nunn-Lugar Comprehensive Threat Reduction (CTR) assistance. In the time period between 1992 and 2008, cumulative CTR assistance to Kazakhstan has culminated to $341 million. At the "2012 Seoul Nuclear Security Summit" in March 2012, Presidents Obama and Nazarbayev reaffirmed bilateral cooperation in the areas of nuclear nonproliferation. President Obama went on to say, "The close relationship between our two countries extends beyond just the nuclear security issue, so this meeting will give us an opportunity to discuss the cooperation that we have built over the last several years with respect to Afghanistan and the help we've received in supplying our troops and helping to assist the Afghan government." In addition to nuclear nonproliferation, the U.S. and Kazakhstan maintain strategic economic and political relations. The U.S. oil company, Chevron, became the first major investor in Kazakhstan in 1993 with the establishment of the TengizChevroil joint venture. Through the Bolashak Program, Kazakh students study overseas. Currently, there are over 3,000 Bolashak students around the world of which 800 are studying in 42 universities throughout the United States.