Fig. 2

Bivariate relationship between OOPE and economic development at the provincial level between 2011 and 2015 (n = 84). Note: Provincial GDP per capita data was extracted from China Statistical Yearbook 2016. OOPE was log-transformed to normalise the distribution. OOPE in 2011 and 2013 were converted to 2015 price-based GDP deflator. Each province (n = 28) has three observations