Most of the caffeine that is removed when making decaffeinated coffee gets put into caffeinated soft drinks, aspirin, and over the counter stimulants.
Only 5% of the caffeine in a cola drink, for example, actually comes from kola nuts.
The rest is added artificially.
Despite the removal of caffeine, many decaffeinated drinks still have about 1 to 2% of the original caffeine remaining in them.
The first commercial decaffeination process was invented by Ludwig Roselius and Karl Wimmer in 1903.