The development of the Kingdom’s economy has generated a massive increase in the volume of mail which the postal services have had to handle. In a continuing process of expansion, the Fourth Development Plan provided for five new central post offices (in the Holy City of Madinah, Abha, Buraidah, Jizan and Skaka) to complement the three main postal complexes in Riyadh, Jeddah and Dammam. Indeed, an efficient postal network now covers all the cities and villages of the Kingdom, with 488 main and 175 branch post offices. The total number of domestic correspondence has increased from 19.1 million postal items in 1970 to 345.6 million items in 1999.