This is your risk of dying of a stroke or of complications following a stroke. Many of the things that cause strokes and heart attack are similar. Both are largely a result of hardening of the arteries (arteriosclerosis) although a small fraction of the strokes are a result of bleeding rather than vessel narrowing and clotting. High blood pressure tends to be more important as a cause of stroke than for heart attack, for example. Smoking and cholesterol are also important, of course.
The Stroke Association has more information about Stroke Prevention. Prompt evaluation and treatment can make a difference in the outcome of a stroke--some treatments need to be given within 3 hours of the onset of the stroke to have their best effect.