Any measurement in which the number of individuals in a study population that display cerebrovascular lesions at a point in time or develop cerebrovascular lesions within a determined period of time are compared to the total number of individuals in the study population. Often expressed as a percentage but could be expressed as a ratio. A cerebrovascular lesion is a non-tumorous, that is non-neoplastic, lesion of the brain which involves or is caused by a component of the vascular system and blood supply of the brain. These include strokes, any of a group of pathological conditions characterized by sudden, non-convulsive loss of neurological function due to brain ischemia and/or intracranial hemorrhages.