The central government's tax collection service, the Agencia Tributaria, has said that it managed to get hold of an extra 15.1 billion euros in 2018 in its efforts to prevent and to counter tax fraud.
This is up on 14.8 billion extra collected in 2017, but 500 million short of the expected figure. In most years since 2008, the government has fallen short of its target to recover unpaid tax.
Since 2004, when current records began, it says it has got back 156.1 billion in unpaid taxes through its publicity campaigns and inspections.
Last year, a special unit was set up to investigate the tax payments of high-net-worth families, which in 2018 alone led to 347 million being collected in 494 different cases opened, 44% more cases than the previous year for the whole group.
The tax office has highlighted the rise in warnings sent out to landlords in the last year. Because of increased sharing of information with platforms like Air BnB, 700,000 notices have been sent out in 2019, up from 258,000 a year ago. It says that in three years, 122,000 new taxpayers with rental properties have come forward to declare income.