But for countries which use price stabilising policies extensively, such as India, China and Japan, price volatility is substantially less than international markets. It should be noted, however, that comparison across countries is complicated by many factors, including product quality or attribute differences which may affect the diversity of movement in market prices. Figure 2.3 plots the nominal annualised historic volatility for the same three crops over 1957-2009. While one can distinguish spikes in the volatility due to the 1971-73 and the 2007/08 price hikes, there is no apparent trend in the series, suggesting that volatility of observed prices may increase for certain periods, but then return to normal levels.