Every match win is worth points equal to how deep that round is: a 1st Round win is worth 1 point, 2nd Round 2, 3rd Round 3, Semi-Final 4, and winning the Final is worth 5. A beer's all-time points are simply every one of those added up, across every year it's competed - so consistently going deep matters as much as winning it all once.
Plate competition wins (the wooden-spoon knockout for 1st Round losers) count too, but at half weight, since it's a consolation bracket rather than the main event.