The annual budgets have grown steadily larger. The approved budget for 1973 called for revenues of 7,057 million leva and expenditures of 7,035 million leva. In 1970 actual revenues totaled 5,723 million leva, the expenditures amounted to 5,650 million leva. Usually about 90 percent of budgetary revenue has been derived from operations of the economy, and the remainder has been raised through a variety of levies on the population. The largest single item of revenue--more than 30 percent of the total--has been collected in the form of a turnover tax on sales that has been passed on to the ultimate consumer. The second most important revenue source has consisted of levies on enterprises in the form of a profits tax, a tax on fixed capital (interest charge) and miscellaneous other deductions from income. Social security taxes based on payrolls have been the third major source. Levied at a rate of 12.5 percent through 1972, the social security tax was raised by 20 percent in 1973 in order to meet rising costs. In 1972 about four-fifths of the turnover tax and two-thirds of the revenue from taxes on profits and capital was to be derived from industry. In December 1972 the BKP Central Committee plenum embarked upon a gradual modification of the income tax system that would eventually lead to a total abolition of income taxes for wage earners and collective farmers by 1980. Initially, the existing system is to be improved by introducing unified taxation for all blue- and white-collar workers and collective farmers and by establishing a tax exemption equal to the official minimum rate of pay. Gradual elimination of all income taxes for these population groups in the 1976-80 period is to be synchronized with the contemplated reform of wage scales. At the same time a system of progressive taxation is to be introduced on incomes derived from activities in the private sector that are not in conformity with the amount of labor invested. The most complete recent information on budgetary expenditures is available from the approved budget for 1972. Out of a total outlay of 6,514 million leva, 3,224 million leva was earmarked for the national economy, and 2,065 million leva was set aside for social and cultural needs. The remaining undisclosed balance of 1,225 million leva, or 19 percent of the total outlays, must have included expenditures for defense, internal security, and government administration. The social and cultural expenditures included; social security payments, 1,054 million leva; education, 532 million leva; public health, 303 million leva; culture and arts, 83 million leva; and science, 93 million leva, in addition to 235 million leva to be provided by research organizations and economic trusts.