Japan's most famous magazine Famitsu has four critics review games on a scale of 1-10 with 10 being the best. The critics write very brief remarks along with their score. The scores are then tallied up to 40.
Game site Siliconera has looked at "top tier" Famitsu review scores over the past decade - scores between 36 and 40. Scores below are not factored into this chart. It does indicate several trends, including a spike in games getting a "36" as well as games getting a "40".
Make of it what you will.