Silver Book Fact
Close to 1/3 of American adults with high blood pressure do not know they have it, which increases the risk of related complications and other diseases.
Jones D, Hall J. The National High Blood Pressure Education Program: Thirty years and counting. Hypertension. 2002; 39(5): 941-42. http://hyper.ahajournals.org/cgi/reprint/39/5/941.pdf