Statistics really can calculate average sexual frequency. But an average describes a group of people; it does not prescribe a norm for a particular couple.
One couple has sex twice a week and one partner finds that painfully infrequent. Another has sex a few times a month and both are completely satisfied. If we look only at the number, the first couple appears “more sexually active.” If we look at satisfaction, the picture changes entirely.
Desired frequency also changes with relationship duration, stress, children, health and life circumstances.
So I’m less interested in comparing ourselves with the statistical neighbour. A much more informative question is: How often would you personally want sex if you removed the idea of how often you are “supposed” to want it?