In 2009, Burkina Faso spent 0.20% of GDP on research and development (R&D), one of the lowest ratios in West Africa. There were 48 researchers (in full-time equivalents) per million inhabitants in 2010, which is more than twice the average for sub-Saharan Africa (20 per million population in 2013) and higher than the ratio for Ghana and Nigeria (39). It is, however, much lower than the ratio for Senegal (361 per million inhabitants). In Burkina Faso in 2010, 46% of researchers were working in the health sector, 16% in engineering, 13% in natural sciences, 9% in agricultural sciences, 7% in the humanities and 4% in social sciences. Burkina Faso was ranked 118th in the Global Innovation Index in 2020, down from 117th in 2019.