Oil and gas exports have increased substantially (in 2003 Equatorial Guinea was ranked third among Sub-Sahara African producers behind Nigeria and Angola) and will drive the economy for years to come. The GDP increased by 105.2% in 1997, and real GDP growth reached 23% in 1999, and initial estimates suggested growth of about 15% in 2001, according to IMF 2001 forecast. Per capita income grew from about $1,000 in 1998 to about $2,000 in 2000. The energy export sector is responsible for this rapid growth. Oil production has increased from to between 1998 and early 2001. There is ongoing additional development of existing commercially viable oil and gas deposits as well as new exploration in other offshore concessions.