Deflation is a prolonged drop in wages, prices and the value of assets like stocks and houses.

NPR: Fed Likely To Stick With Low-Rate Stance This Week

Then, when inflation fell in the 1990s, they benefited again from a step jump in the value of their biggest asset as low interest rates stimulated a prolonged housing boom.

ECONOMIST: Bagehot

That said, the competitiveness of British companies has been improved by the prolonged fall, since the great crash of 2007 to 2008, in the value of the pound.

BBC: It's trade or bust for Britain

The SR-71 has proven its value as a complementary system to U.S. space-based reconnaissance assets during the prolonged period from 1985 to 1987 when the United States was unable to place new satellites in orbit.

CENTERFORSECURITYPOLICY: Center for Security Policy | Congress Must Preserve A Vital Strategic Reconnaissance Capability �� The SR-71