reporting percentages

When reporting percentages it's useful to give the absolute figures too e.g.

"65% of people reported improved symptoms after treatment (13/20), only 6% of people reported negative side effects (1/17)".

The absolute numbers are important because they show us that even though 65% sounds high, it's based on a modest sample size. The denominator is useful as we see that the two results are based on different number of responses; 20 in one group and only 17 in the other.