A Cityjet Canadair CRJ-900 on behalf of SAS, registration EI-FPE performing flight SK-1480 from Billund (Denmark) to Stockholm (Sweden) with 55 passengers and 4 crew, was climbing out of Billund when at about FL190 the crew initiated an emergency descent to 9000 feet due to the loss of cabin pressure, the passenger oxygen masks were deployed. The aircraft climbed to FL100 subsequently and continued to Stockholm for a safe landing about one hour after stopping the climb at . . .