Automobile manufacturers handle their production statistics based on two information dimensions:
Model Year
The Model Year is defined as the period of time an auto manufacturer determines its sales, marketing and engineering support for a particular vehicle. The Model Year view is utilized by Japan, USA, Canada, Australia, New Zealand, Middle East, and other coutnries.
In the USA, the Model Year cannot exceed the January of the previous year. For example, a 1991 model can be declared from January 1990 forward to whenever the manufacturer deems the model is no longer offered. For the 1991 BMW 8 Series, the North American Model Year ran from January 1990 until late June 1991.
In certain countries, as in the example of North America, the VIN number has a digit that represents the Model Year of the vehicle. The 10th digit is an alpha-numeric code that represents the model year of the vehicle. For the 8 Series, the 10th digit represented the following years:
- M = 1991
- N = 1992
- P = 1993
- R = 1994
- S = 1995
- T = 1996
- V = 1997
- W = 1998 (Middle East)
- X = 1999 (Middle East)
Calendar Year
The Calendar Year is defined as the January through December time frame an auto manufacturer uses to report annual production for a variety of reasons, including financial reporting of income derived from production.
Many countries, including the European Union, do not recognize the Model Year method and instead use the Calendar Year definition when reporting manufacturing by model number. However, typically it is understood that the model year change-over occurs in September of every year for BMW when engineering changes are implemented following the summer holiday. So although the European Union does not recognize the model year designation vis-a-vis other countries, it nonetheless is considered a newer model year when the changeover occurs in September.
For markets that use the Model Year designation, many unscrupulous sellers will utilize the calendar year production to advantage their rareness selling pitches. For example, in the USA, the 1997 model year for the M73 850CiA began in mid-April 1996 and concluded late July 1997, with 166 cars coded with the 1997 VIN. However, some people will claim that their car is one of 85 M73 850CiA's built for North America in 1997. When pressed for proof, ~50% of the claims will prove false as the car was built as a 1997 in the 1996 calendar year.