The survey done by Roy Morgan Research shows a sharp decrease in amount of listening to radio - down about 20% since 2004. According to the report, the national average of radio listening dropped from 15.5 hours each week in 2004 to about 12 hours as of June 2011. While a Nielsen report on radio also shows a decrease, their study found the listening loss was approximately 14% over the same period. The Nielsen report covers Australia's five capital cities. The Sydney Morning Herald newspaper has more details here.