The salaries of administrative and technical workers were about 20% higher than those of production workers. In the late 1980s, with wages in manufacturing firms having 500 or more workers indexed at 100, enterprises with 100 to 499 employees were indexed at 79, those with thirty to ninety-nine employees at 64, and those with five to twenty-nine employees at 56.6. The gap between wages paid to secondary school and college graduates was slight but widened as the employees grew older; wages peaked at the age of fifty-five, when the former received only 60 to 80% of the wages of the latter.