International influence and propagationAccording to observers, such as Gilles Kepel, Wahhabism gained considerable influence in the Islamic World following a tripling in the price of oil in the mid-1970s and the progressive takeover of Saudi Aramco in the 1974–1980 period. The Saudi government began to spend tens of billions of dollars throughout the Islamic World to promote Wahhabism, which was sometimes referred to as "petro-Islam". According to the documentary called The Qur'an aired in the UK, presenter Antony Thomas suggested the figure may be "upward of $100 billion".
Its largess funded an estimated "90% of the expenses of the entire faith", throughout the Muslim World, according to journalist Dawood al-Shirian. It extended to young and old, from children's madrasas to high-level scholarship. "Books, scholarships, fellowships, mosques" (for example, "more than 1,500 mosques were built from Saudi public funds over the last 50 years") were paid for. It rewarded journalists and academics, who followed it and built satellite campuses around Egypt for Al Azhar, the oldest and most influential Islamic university.
This financial power has done much to overwhelm less strict local interpretations of Islam, according to observers like Dawood al-Shirian and Lee Kuan Yew, and has caused the Saudi interpretation to be perceived as the correct interpretation in many Muslims' minds.
The Saudis have spent at least $87 billion propagating Wahhabism abroad during the past two decades, and the scale of financing is believed to have increased in the past two years. The bulk of this funding goes towards the construction and operating expenses of mosques, madrasas, and other religious institutions that preach Wahhabism. It also supports imam training; mass media and publishing outlets; distribution of textbooks and other literature; and endowments to universities (in exchange for influence over the appointment of Islamic scholars). Some of the hundreds of thousands of non-Saudis who live in Saudi Arabia and the Persian Gulf have been influenced by Wahhabism and preach Wahhabism in their home country upon their return. Agencies controlled by the Kingdom's Ministry of Islamic Affairs, Endowments, Da'wah and Guidance are responsible for outreach to non-Muslim residents and are converting hundreds of non-Muslims into Islam