There's no need to. They simply calculate (at least in this case) CPI based on how the government calculated inflation in 1990 and separately in 1980, after Federal Reserve Chairman Paul Volcker had the U.S. Bureau of Labor Statistics change the way the calculated the CPI.

I can't speak for their calculations on middle 20% unemployment figures though. If someone can legitimize or justify how they get there, I'd love to hear!  

This week Forbes did have the balls to come out this week and say that the real unemployment rate is DOUBLE the official rate from the U.S. Bureau of Labor Statistics, putting it over 14%!