Do the grading companies have a set standard SN minimum or maximum to check the serial numbers against? Is there an official definition of "low" and "high" when it comes to numismatics and serial numbers? Is it strictly based on how many leading 0's or 9's are in the SN? So for low serial numbers: 3 leading zeros = 99,999 bills. That's a lot. Probably not "low"? 4 leading zeros = 9,999 bills. Better. 5 leading zeros = 999 bills. Definitely low? Same idea for high serial numbers. How many leading nines until it's considered a high SN? OR, is "low" and "high" based on some other criteria? Like the serial number's ratio to the total number of bills produced or something? I've tried Googling grading standards for low/high serial numbers, but without any luck. Thanks for any help.