Suppose the Social Security tax rate is 6.2 percent of earnings up to a maximum of $117,000, beyond which there is no additional tax. Zia has earnings of $140,000 and Paul has earnings of $80,000. Zia's average tax rate is |:| percent and Paul's average tax rate is |:| percent. (Round your responses to two decimal places.) The Social Security tax is an example of a l:' tax. progressive regressive proportional