PSL Club Agreement Question

I apologize in advance if this is a dumb question, but I am looking at purchasing a PSL in the club level from the team's marketplace. For each seat it mentions a club agreement with a term length, percentage, and a beginning year. The term length makes sense to me (the length of time that you are must pay for tickets whether you want them or not); however, I don't fully understand the percentage and beginning year. Are the season ticket prices locked in for the term length or is the percentage the amount they can raise prices year over year for the term length? Thank you in advance!