Who cares how the rich spend their money?

Well, perhaps everyone should these days. Consumer spending accounts for roughly two-thirds of U.S. gross domestic product, or the value of all goods and services produced in the nation. And spending by the rich now accounts for the largest share of consumer outlays in at least 20 years.

According to new research from Moodys Analytics, the top 5% of Americans by income account for 37% of all consumer outlays. Outlays include consumer spending, interest payments on installment debt and transfer payments.

By contrast, the bottom 80% by income account for 39.5% of all consumer outlays.

It is no surprise, of course, that the rich spend so much, since they earn a disproportionate share of income. According to economists Emmanuel Saez and Thomas Piketty, the top 10% of earners captured about half of all income as of 2007.