Missouri’s tax revenue may be adversely impacted by a Nationwide increase in income inequality. That’s according to a report released by a leading credit rating agency that says the State’s average annual tax revenue growth has declined sharply in recent decades. Back in the 1970’s, Missouri averaged more than nine percent annual growth. However, between 2000 and 2009 it averaged just 1.8 percent. For several decades, household incomes have been rising a lot faster for the top one percent of earners than for median households causing the income gap.