The first factor that has caused Indonesia's economy to grow so much is the rich natural resources that Indonesia possesses. Geologists have discovered huge amounts of oil, coal, and valuable minerals underneath and off the coast of Indonesia. In addition to the vast mineral wealth, Indonesia's soil is very fertile because of all of the volcanoes along the archipelago. This fertile soil makes Indonesia a great place for growing valuable crops such as rubber, palm oil, cacao, and coffee. According to The Heritage Foundation 2014, these valuable resources combine to add $US480 billion to Indonesia's economy every year. As the world develops more every year, the demand for such resources continues to increase, making Indonesia richer and richer.