I suppose the better question is how much do the top 10% earn as a percent of GDP. The bottom 20% should not pay income tax as they are J.A.M.S.. If we have an inequality problem then the wealthier will have to pay more. If not then no worries. Once levels of inequality reach a certain point we know that things can go pear shape. It is not helpful for the ruling class to respond with a policy of  'let (the deplorables) eat cake' .