Wheel Offset

As all know, the Crown Vic has been produced for years in both a commercial/police/taxi package and in a consumer package. In the early years it may have been probable that both used the same wheels. At some point, police requested beefier wheels to handle curbs, etc. and the commercial package soon came with stronger rims and tires. The offset changed as a consequence of the redesign of this wheel. At some point as well, the wheels of the consumer package were changed and so did the offset of each wheel. Please correct any of this, because my understanding (or lack thereof) of the history of the Crown Vic wheel is quite important to my predicament.

There are several questions to this issue. Did the offset of the commercial and the consumer models change in the same years? Did they change to the same measurements for each package? As the package models become newer, do the offsets go in different directions, i.e. is the offset of new commercial models low now while the offset for new consumer models high now? Can you tell the offset of a Crown Vic by just knowing the year of manufacture or must you also know the type of package as well?