Logistics has an ancient history. A quick look back can be enlightening. Its history dates to the wars of the Greek and Roman empires in which the military officials called logistics were responsible for supplying and distributing needed resources and services. Providing them had an important and essential role in the outcomes of these wars. These logistics also worked to damage the stores of their enemies while defending their own. This gradually guided the development of current logistics systems. In each country, a huge amount of money is spent annually in logistical activities. For instance, in 2003 US logistical activity costs were 8.5% of the country's GDP. Given that the US GDP in 2003 was approximately $12,400 billion, the logistical activity cost was approximately $1054 billion. Many people believe that logistics is a word, but from a semantics point of view its origin was from ancient Greek and meant the "science of computation." In fact, it is originally from combat environments and not from business or academia. It is also thought that the ancient Greeks referred the word logistikos to military officers who were expert in calculating the military needs for expeditions in war.