Taxable Income and Total Tax Liability are in thousands.

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

Required:

a$.$ If the federal tax system was changed to a proportional tax rate structure with a tax rate of $17\mathrm{.}10\%,$ calculate the amount of tax liability for $2021$ for all taxpayers.

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