68 (1 point) In Techland, from 1990 to 2020, holding technology and human capital fixed, increasing physical capital per worker from $25,000 to $100,000 would have led to a doubling of real GDP per worker, from $40,000 to $80,000. However, not only did physical capital per worker increase from $25,000 to $100,000, but technological progress shifted the productivity curve upward so that real GDP per worker actually increased from $40,000 to $320,000. What share of the annual growth rate of real GDP per capita was attributable to increasing physical capital per worker? 2.0% 4.5% 8.75% 17.5%