Over the last decades, the distribution of tax burden between the three main administrations has changed significantly. The share allocated to the state has tended to decline, while that allocated to the social security institutions and local governments has grown The higher tax rate of social security is due to the general upward trend of social spending, particularly the higher spending on pension and health insurance systems. The pension expenditure grew from 11% of the GDP in 1981 to 13% in 2007, and health spending increased from 6% of the GDP to 10% in 2006 over the same period.