A successful tax policy has succeeded in revealing the true extend of wealth inequality in Spain, generating considerable revenue for regional governments.

Between 2011 and 2017 Spaniards making more than €30 million increased by 74%, according to data released by Spanish tax authorities. At the same time, citizens who declared property worth more than €1.5 million grew by 35%.

The surge in numbers is the result of a devolved administration tax on individual “net worth,” if their assets exceed €700,000, on the top of income or capital gains. Individual asset tax income has been devolved. In Madrid, this category of taxpayers pays no additional tax at all while Catalonia collects just under half a billion Euro a year.

Part of the reason why the super-rich population has grown so much, according to El Pais, is that in 2012 the Mariano Rajoy government introduced a tax amnesty that uncovered €40bn in undeclared wealth. In 2013, the government forced individuals to declare international assets or face a stiff fine, uncovering an additional €156bn in assets.