Real GDP has grown in a country at 4% per year for the last 30 years. The labour force has grown at 1% per year and the quantity of physical capital has grown at 5% per year. A 1% increase in average physical capital per worker (other things equal) raises productivity by 0.5%. Average education has not changed. How much has technological progress contributed to productivity growth? Q 0.5% v 1% X 2.5% O 5%