I suspect a lot of people are looking for an excuse to not renew and the increase, however small, has given them that excuse. There will be various reasons why people feel like that which I won't go into.
I have two season tickets and was being priced out of East stand level two at £900 each. So I moved to South stand level 3 and now pay £598 for two season tickets. I know that not everyone will be able to bag a seat in the south stand but why not at least try if it's for financial reasons that you aren't renewing? £15 per game is the equivalent to what I pay when I watch my home town club, Barrow, in the National League.