While Badge(r)s features player levels, the time of awarding those is not had defined. Hence this somewhat complex statistics to monitor/compare leveling speed of players. Measured time is between first production of certain badge(!) levels (last 25% or 50% of levels).
Link: Time per Latest Badge Levels
This is a statistics from the player group. There are many more Statistics. Stay up to date with (most) of Badge(r)s statistics via the Significant Statistics Changes page.