Passage: In 1850, old-growth redwood forest covered more than 2,000,000 acres (8,100 km2) of the California coast. The northern portion of that area, originally inhabited by Native Americans, attracted many lumbermen and others turned gold miners when a minor gold rush brought them to the region. Failing in efforts to strike it rich in gold, these men turned toward harvesting the giant trees for booming development in San Francisco and other places on the West Coast. After many decades of unrestricted clear-cut logging, serious efforts toward conservation began. By the 1920s the work of the Save the Redwoods League, founded in 1918 to preserve remaining old-growth redwoods, resulted in the establishment of Prairie Creek, Del Norte Coast, and Jedediah Smith Redwoods State Parks among others. Redwood National Park was created in 1968, by which time nearly 90% of the original redwood trees had been logged. The National Park Service (NPS) and the California Department of Parks and Recreation (CDPR) administratively combined Redwood National Park with the three abutting Redwood State Parks in 1994 for the purpose of cooperative forest management and stabilization of forests and watersheds as a single unit.The ecosystem of the RNSP preserves a number of threatened animal species such as the tidewater goby, Chinook salmon, northern spotted owl, and Steller's sea lion. In recognition of the rare ecosystem and cultural history found in the parks, the United Nations designated them a World Heritage Site on September 5, 1980 and part of the California Coast Ranges International Biosphere Reserve on June 30, 1983.

Question: How much of the California coast was covered with redwoods in 1850?
2,000,000 acres