Changes

The first task was to find the relevant U.S. granted patents, and EP granted patents or published patent applications. This was done for all patents published in years 1975 to 2005. This range of years is more than sufficient; but almost all of the action has taken place in the last ten years or even considerably lesser time in some categories.

usually the most difficult and time-consuming part of a patent analysis, and that was certainly not the case in this research.