Answer
$30.85\%$.
Work Step by Step
$z=\frac{\text{data item-mean}}{\text{standard deviation}}$.
Hence here: $z=\frac{23.6-22.5}{2.2}=0.5$
Using the table, the percentage of data items in a normal distribution that lie above it is $100\%$ minus the percentile that lies below it (we obtain this from the table): $100\%-69.15\%=30.85\%$.
