The Z score for sbp=160 is (160-120)/22=40/22=1.8182 approx.
In the normal distribution table 1.8182 corresponds to 0.9655 approx, or 96.55%. This is the percentage of the population with sbp<160, so 100-96.55=3.45% of the population have stage (or type) 2 diabetes (sbp>160).