Bulgaria revised much of its tax system in 1996. One of the changes states that foreign persons receiving remuneration as lecturers and consultants, royalties, license payments, and remuneration for technical services, are charged with a 32% tax at the time of payment. Personal income tax rates increase progressively from 18% to 50%. The basic corporate or profit tax rate is 36%. A withholding tax of 15% is assessed on dividends. Employers are required to contribute 37% of employees' gross salaries for social security insurance while the employees contribute an additional 2%. The value-added tax on goods and services, introduced on 1 April 1994, was increased from 18% to 22%. Other taxes include a property tax at a rate of 2% to 4%.