Fig. 3From: Spatiotemporal variations in cardiovascular disease mortality in China from 1991 to 2009Temporal changes of the proportion of the population in the counties grouped by CVD death rates to the national population for coronary heart disease (CHD, a) and stroke (b) during the four periods (1991–1995, 1996–2000, 2004–2005, and 2006–2009)Back to article page