and matches going to 90 minutes being rare. However, I don't think a majority of them end within the 80th minute when you factor in the following:

1. Depends on which team has the ball when the clock strikes 90.

2. Games typically don't end on a penalty, so 1 team has to kick the ball out of bounds to end the game.

3. If a team scores a try after the 80th minute, then they must attempt the extras.

4. If a team has been awarded a penalty kick, then I believe the team must be given an opportunity to attempt it. Also, I know the kicker is given 1 min 30 secs to make a forward movement to kick the ball once it is on the tee or the opposing team is allowed to charge the kick. I believe a similar time constraint is given on penalty kicks, but I am not sure if that means the opposing team is now allowed to charge the kick or not.