Among Medicare patients ages 65 and older, atrial fibrillation prevalence increased from 3.2% in 1992 to 6.0% in 2002–with higher prevalence in older patients.
Lakshimarayan, K, CA Solid, AJ Collins, DC Anderson, and CA Herzog. Atrial Fibrillation and Stroke in the General Medicare Population: A 10-year prospective. Stroke. 2006; 37(8): 1969-74. http://stroke.ahajournals.org/content/37/8/1969.full