This is helpful dating an instrument. Not very helpful determining how many of a particular model were built over the course of the company's run. Does anyone have that information? I would think someone has access to that...anyone know for sure?
The basic formula is that the first two digits of the number indicate the year they were built - i.e. a bass starting with "98" indicates that it was built in 1998, "12" indicates that it was build in 2012, etc. After those two digits, the numbers increase based on when they were built in the given year.