From a 2004 article in boston.com (http://www.boston.com/business/globe/articles/2004/04/11/most_us_firms_paid_no_income_taxes_in_90s/)

“The GAO report showed that 61 percent of US corporations paid no federal income taxes from 1996 through 2000, a period of rapid economic growth and rising corporate profits.

An estimated 94 percent of US corporations reported tax liabilities amounting to less than 5 percent of their total income in 2000. The corporate income tax rate is ostensibly 35 percent, but companies are able to reduce their effective burden by claiming various deductions and credits.

US companies paid an average of $11.88 in corporate taxes for every $1,000 in gross receipts, the study said.”