for people younger than 65 years with no risk factors the untreated annual risk of stroke is about 1%, whereas with one or more
risk factors it is about 5%; for people aged 65-75 years with no
risk factors the annual
risk of
stroke is about 4%, and with one or more risk factors it is about 6% per year; and for people older than 75 years with no risk factors the risk of stroke is about 3%-4%, whereas with one or more risk factors it is about 8% (see Box 2) (E1).7,26
from http://www.mja.com.