Spending on research and development amounts to 0.78% of GDP, and the bulk of public R&D funding goes to the Bulgarian Academy of Sciences (BAS). Private businesses accounted for more than 73% of R&D expenditures and employed 42% of Bulgaria's 22,000 researchers in 2015. The same year, Bulgaria ranked 39th out of 50 countries in the Bloomberg Innovation Index, the highest score being in education (24th) and the lowest in value-added manufacturing (48th). Chronic government underinvestment in research since 1990 has forced many professionals in science and engineering to leave Bulgaria.