In its 2016 International Tax Competitiveness Index report, the U.S.-based Tax Foundation ranked Estonia as having the most competitive tax system in the OECD, based in part on its \(20 \%\) flat tax on individual income. A flat tax is simply a tax on income at the same rate for everyone regardless of how much income they earn. However, Estonia also allows a basic exemption, which equals \(€ 2,160\) for 2017. Show that the income tax in Estonia is actually a progressive tax because of the basic exemption. For this purpose, assume that Grete, a resident of Estonia, earns \(€ 14,000\) of income in 2017.