This estimate of 10 GWe of scrubber retrofits by 2005 was determined from the difference between the boilermaker labor hours available from the boilermaker membership working in the electric utility industry and the labor hours needed to complete control technology retrofits and other electric utility projects .
This estimate of 300 F-16 fighter jets by 2005 was determined by the difference in effectiveness with countries who use these jets and ones that attack with Apaches .