In tests, a team can enforce follow-on if they must have a minimum lead of 200 runs after the second innings. However, often the leading team will decide not to enforce follow-on and go on to bat in the third innings, with weather forecasts, condition of the pitch, number of overs bowled in the second innings and bowlers' and fielders' fitness being important factors swaying the decision.
What is the percentage of matches where the leading team chose not to enforce follow-on? I am focused on international cricket, but domestic records can also be included.