that services satisfy higher needs than goods and so as income grows a higher share of income will be used for the purchase of services; changes in the inter-industry division of labor, favoring specialized service activities; outsourcing to countries with lower labor costs; increasing participation of women in the labor force; and trade specialization. The Baumol effect has also been used to describe the reallocation of labor out of agriculture (in 1930, 21.5% of the workforce was employed in agriculture and agriculture made up 7.7% of GDP; by 2000, only 1.9% of the workforce was employed in agriculture and agriculture made up only 0.7% of GDP). In a 2009 study, the economists Benjamin N. Dennis and Talan B. İşcan concluded that after the 1950s relatively faster productivity growth in agriculture was the key driver behind the continuing shift in employment from agriculture to non-farm goods (prior to the 1950s, they determined that Engel's law explained almost all labor reallocation out of agriculture). Economic growth and aggregate productivity In his original paper on the cost disease, Baumol argued that in the long run the cost disease implies a reduction in aggregate productivity growth and correspondingly a reduction in economic growth. This follows straightforwardly from the labor distribution effects of the cost disease. As a larger and larger share of the workforce moves from high-productivity-growth industries to low-productivity-growth industries, it is natural to expect that the overall rate of productivity growth will slow. Since economic growth is driven in large part by productivity growth, economic growth would also slow. The economist Nicholas Oulton, however, argued in a 2001 paper that Baumol effect may counterintuitively result in an increase in aggregate productivity growth. This could occur if many services produce intermediate inputs for the manufacturing sector, i.e. if a significant number of services are business services. In this case, even though the slow-growth service sector is increasing in size, because these services further boost the productivity growth of the shrinking manufacturing sector overall productivity growth may actually increase. Relatedly, the economist Maurizio Pugno described how many stagnant services, like education and healthcare, contribute to human capital formation, which enhances growth and thus "oppos[es] the negative Baumol effect on growth". The economist Hiroaki Sasaki, however, disputed Oulton's argument in a 2007 paper. Sasaki constructed an economic model that takes into account the use of services as intermediate inputs in high-productivity-growth industries and still concluded