CPI长尾

The Long Tail of CPI

春节过去一个月，市场上蔬菜的价格仍停留在节日的价签上。1月CPI出乎意料，达到4．5％，食品价格同比涨10．5％，蔬菜价格涨幅更高达23．0％。到了2月，两三元一颗西红柿，一两元一根黄瓜，茄子每斤5元，苦瓜每斤10元，除节日加价因素外，还有颇多涨价因素。

Another month has gone by since the Chinese spring festival, but the prices of vegetables still stay at the high level. It takes two or three yuan to buy a tomato, one or two yuan to buy a cucumber, five yuan to buy 500g of eggplants, and ten yuan to buy 500g of balsam pears. There are many factors to elevate the prices besides the festival. However, if taking the farm products independent of the cold season into account , such as the corn and the rice, we will find that the logic of the prices is not so linear.The prices of the corn, the wheat and the rice had declined for two months since September 2011. Then the prices of the corn and the rice had risen more than 10% after December. By 20 February 2012, the corn futures' price in Dalian Commodity Exchange had kept rising for three months. This rapid rebound indicates that the prices tend to rise rather than to decline. The rising prices improve the farmer's incomes and expand their consumptions. But the consumptions will be offset by the costly necessaries like meat and vegetables. As the incomes of the poor keep increasing, more goods will be listed as necessaries. This is why the prices are readily to go up and hardly to fall down.