Indicators for targets 9.b and 9.c have data available. Globally, energy efficiency and the use of cleaner fuels and technologies reduced carbon dioxide emissions per unit of value added by 13 per cent between 2000 and 2013. Although expenditure on research and development continues to grow globally, the poorest countries, especially those in Africa, spend a very small proportion of their GDP on such expenditure. In 2013, global investment in research and development stood at $1.7 trillion (purchasing power parity), up from $732 billion in 2000.