It currently provides a 9% taxdeductionfrom net income for businesses engaged in "qualified production activities" in the U.S. Those activities include manufacturing a product, selling, leasing or licensing it, and engineering and software activities related to that production.
About 40% of that revenue would be a result of not extending the 2001-03 tax cuts for high-income households and another 30% would come from the deduction cap (so you could wipe that off the books already).
But note again that the largest group excluded from paying incometax because of special tax expenditures are seniors, who get a bigger standard deduction than younger folks and more importantly, special tax treatment for their Social Security benefits.