CBO reported that for the 1979–2007 period, after-tax income (adjusted for inflation) of households in the top 1 percent of earners grew by 275%, compared to 65% for the next 19%, just under 40% for the next 60% and 18% for the bottom fifth.The share of after-tax income received by the top 1% more than doubled from about 8% in 1979 to over 17% in 2007. The share received by the other 19 percent of households in the highest quintile edged up from 35% to 36%. The major cause was an increase in investment income. Capital gains accounted for 80% of the increase in market income for the households in the top 20% (2000–2007). Over the 1991–2000 period capital gains accounted for 45% of market income for the top 20%.