Productivity is a measure of output divided by a measure of input (see Feenstra et al., As for income, three-years averages (2009-11) also are used for total factor productivity, labour force, human and physical capital accumulation to reduce the impact of short-run variations. The quality of the labour force is traditionally captured by the stock of human capital and TFP, while the size is proxied either by the employment rate or the labour force participation rate.