Tax allowances (e.g. voluntary pension contributions, long-term savings to finance construction, dividends that have been taxed at the company level), deductions (e.g. mandatory and some voluntary health care contributions, mortgage interest payments for residential housing) and exemptions (e.g. 25% of wages under a threshold, most pension payouts) are so generous that less than 40% of the income of the top 1% is deemed taxable (Alvaredo and Londono, forthcoming). This percentage decreases further with income - for the top 0.01%, only 11% of their income is taxable. The law has hitherto stated that if an individual is not required to file a PIT return because gross income is lower than the filing threshold, then the withholding tax operates as a definitive tax.