5. Assume that the annual income of Mr. Smith is OMR 200,000. Based on the following tax principles calculate the average tax rate and draw two diagrams to show average and marginal tax curves Tax base Regressive tax rate Below 10,000 25% 10,000 -- 20,000 20% 20,000 --40,000 15% 40,000--80,000 10% 80,000 and above 5%