From wikipedia:

Classification of blood pressure for adults
Category systolic, mmHg diastolic, mmHg
Hypotension < 90 < 60
Normal 90 – 120 and 60 – 80
Prehypertension 121 – 139 or 81 – 89
Stage 1 Hypertension 140 – 159 or 90 – 99
Stage 2 Hypertension ? 160 or ? 100