"The Economist" has criticised green belt policy, saying that unless more houses are built through reforming planning laws and releasing green belt land, then housing space will need to be rationed out. It noted that if general inflation had risen as fast as housing prices had since 1971, a chicken would cost £51; and that Britain is "building less homes today than at any point since the 1920s". According to the independent Institute of Economic Affairs, there is "overwhelming empirical evidence that planning restrictions have a substantial impact on housing costs" and are the main reason why housing was two and a half times more expensive in 2011 than it was in 1975.