Let make sure I understand this right
Top 1%
AGI earnings: $343,927 and over
% of all income taxes paid: 36.73
Top 5%
AGI earnings: $154,643
% of all income taxes paid: 58.66
Top 10%
AGI earnings: $112,124
% of income taxes paid: 70.47
Top 25%
AGI earnings: $66,193
% of income taxes paid: 87.30
Top 50%
AGI earnings: $32,396
% of income taxes paid: 97.75
Bottom 50%
AGI earnings: below $32,396
% of income taxes paid: 2.25
In other words.
top 0-1% pays 36.73% of taxes
top 1.001 to 5% pays 58.66-36.73%= 21.93% of taxes
top 5.001 to 10% pays 70.47-58.66%=11.71% of taxes
top 10.001 to 25% pays 87.30-70.47%=16.93% of taxes
25.001 to 50% pays 97.75-87.30%= 10.45% of taxes.
and the bottom 50% pays 2.25% of taxes
and since the top 1% pays the most taxes(almost twice any other bracket considered), we should raise taxes on every until everyone is paying the proper amount of taxes despite the amount they actually make. Is that what you are implying??
What I am saying is that the federal government needs a hell of lot less money that it collects to do its constitutionally mandated responsibilities, and every citizen should feel and have responsibility to help fund those constitutionally mandated responsibilities.
A flat tax is the most equitable and fair way to accomplish that without putting excessive pressure on the poor and without encouraging the rich to take and invest their money elsewhere.
In a true flat tax system, the person earning one million dollars would pay one thousand times more in federal income taxes than the one who makes one thousand dollars. But both would pay something and both would experience a proportional increase or decrease in the tax rate. That puts both on equal footing as citizens with comparable motives to demand good government rather than promote government that increases its own power and fortune via income redistribution. It takes class warfare out of the equation and provides excellent motives for all to do what they can to improve their circumstances.
So you are suggesting a flat income tax or a national flat sales tax?
If you are suggesting the former, the amount each person pays in taxes, in the manner you have used, will still looked the same!!
In other words, the top 50% will pay approx 98% of the taxes! Reason--the top 50% makes about 98% in the amount of total wages!
On the other hand, if you are talking about a national flat sales tax, then it will seem equitable until one realizes that, using an average cost of living, those on the bottom rungs will pay more in taxes than those at the top. The reason why is that people with lower incomes will use more of their income to survive and therefore will pay more of their income in taxes. Note

eople in the top brackets need not spend all or even most of their income to survive. What happens if a fellow in the upper brackets only spend 1% of their income and invest the rest? Are we going to tax the purchase of his investments as a sale? In the end, that would encourage investment outside the US.
Bottomline--there is no universally "fair tax" system. Your concept of "equitable" is probably due to the idea that if everyone pays equal percentage then there is no complaint. There will be complaints, as you have noted in your op!!