9 Why does GDP underestimate the actual amount of output produced in an economy Percent 14 12 10 8 0 4 2 0 2 Year to Year Percentage Change in Nominal and Real GDP 1960 1980 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 Years Change Real GDP Change Nominal GDP