WASHINGTON (AP) — U.S. Federal Reserve Chair Alan Greenspan has died at the age of 100. He died on Monday from complications of Parkinson’s Disease, said his wife of 29 years, NBC News correspondent Andrea Mitchell. In his 18½ years at the helm of the Fed, Greenspan presided over a sustained era of American growth and prosperity, yet one that ended with devastating consequences in 2008, two years after he had left the central bank. Greenspan was so respected during his many years as head of the world’s most influential central bank that by the time he stepped down in 2006, he was widely celebrated as the “Oracle’’ and “Maestro.’’