Bulgaria has an open, upper middle income range market economy where the private sector accounts for more than 70% of GDP. From a largely agricultural country with a predominantly rural population in 1948, by the 1980s Bulgaria had transformed into an industrial economy with scientific and technological research at the top of its budgetary expenditure priorities. The loss of COMECON markets in 1990 and the subsequent "shock therapy" of the planned system caused a steep decline in industrial and agricultural production, ultimately followed by an economic collapse in 1997. The economy largely recovered during a period of rapid growth several years later, but the average salary of 1,036 leva ($615) per month remains the lowest in the EU. More than a fifth of the labour force are employed on a minimum wage of $1.16 per hour.