Due to environmental pressures and the restrictive governmental regulations enforced by OPA, substantial proposals of exploration and production in the United States have been withdrawn. As a result of major companies withdrawing their plans to drill, many smaller, independent producers had entered to make a profit. By October 1993, 93% of all oil and natural gas exploration and drilling were from independents producers. Of these new exploration projects, approximately 85% of drilling operations were in the Gulf of Mexico. The independent oil producers generated nearly 40% of the crude oil in the United States and 60% of domestic natural gas.