This graphic is based on the percentage of income paid to taxes. A family making $500k a year paying a higher dollar amount than one making $50k a year is expected, but the higher earners should also be paying a higher percentage because 20% to them means a lot less sacrifice than 20% to a low income family. The sacrifice of not buying that third or fourth house is a lot less than whether the low income family goes to the doctor for a checkup.