Carlyle Group co-founder David Rubenstein stated that the ballooning US debt, which stands at $40 trillion, weakens national security as the country now pays more in interest ($1.25 trillion annually) than on national defense. This annual interest expense represents a record 18.5% of federal government revenue, surpassing the previous peak of 18.4% set in 1991. Rubenstein added that rising interest rates make housing and borrowing more expensive.