At its core the relationship between population and development is primarily, though not exclusively, an economic one. It is about the aggregate consumption and production of resources, and the balance between consumption and production. Populations consume ‘resources’. These may be food or energy or other naturally occurring resources, as well as other ‘resources’, such as the cultural resources created by societies and/or provided by the government, such as schools or hospitals or roads. The economy concerns the production of all these resources. The essence of ‘development’ has been that this resource base has been consistently expanding. Globally, there is now more food and energy being produced than ever before. More people are attending schools or have access to medical care than ever before. However, the population has also been growing. The more people there are, the greater the resource base needs to be if average consumption levels are to be sustained. Per capita production (the average amount of any resource available per person in the population), and not merely gross production, needs to be sustained where there is population growth.