A cohort study is conducted to assess the association between clinical

characteristics and the risk of stroke. The study involves n=1,250 participants who are free of stroke at the study start. Each participant is assessed at study start (baseline) and every year thereafter for five years. The following table displays data on hypertension status measured at baseline and hypertension status measured two years later.

2 Years: Not Hypertensive
2 Years: Hypertensive
Baseline: Not Hypertensive
850
148
Baseline: Hypertensive
45
207

Compute the prevalence of hypertension at baseline.