Taxable Income and Total Tax Liability are in thousands.

Ranges of Adjusted Gross Income
Item	Under $15,000				$15,000 to under $30,000				$30,000 to under $50,000				$50,000 to under $100,000				$100,000 to under $200,000				$200,000 or more
Number of returns		33,998,665				29,548,721				27,127,608				34,537,027				20,094,853				7,788,785
Taxable income	$	21,439,540			$	213,668,669			$	578,082,715			$	1,661,992,914			$	2,055,707,167			$	3,408,931,866
Total tax liability	$	1,891,136			$	18,881,170			$	59,565,261			$	218,856,282			$	343,280,695			$	945,200,723
Average tax rate*		8.82	%			8.84	%			10.30	%			13.17	%			16.70	%			27.73	%

*The average tax rate is total tax liability divided by taxable income.

Required:

If the federal tax system was changed to a proportional tax rate structure with a tax rate of 17%, calculate the amount of tax liability for 2017 for all taxpayers.

What is the amount and nature of difference from actual tax liability specified in the above table?