Revenue for private Canadian radio broadcasters rose 3.7 percent to $1.6 billion in 2011, 97.7 percent of which was from advertising, Statistics Canada said. \"The profit margin before interest and taxes was 19.4 percent in 2011, up from 19.1 percent in 2010, as profits totaled $313 million,\" the agency said. \"However, the margin was lower than the 21.1 percent profit margin recorded in 2008, just before the economic slowdown.\" The FM radio sector had operating revenues of $1.3 billion in 2011 with a profit margin before interest and taxes of 21.5 percent, up from 21.3 percent in 2010, StatsCan said. The shrinking AM sector\'s operating revenues grew by 1.1 percent to $311 million and profitability grew from 10.1 percent in 2010 to 10.6 percent. Since 2009, 16 Canadian AM stations have gone off the air, the report said.