Shia–Sunni relations
Shia–Sunni discord in Iraq starts with disagreement over the relative population of the two groups. According to most sources, including the CIA's "World Factbook", the majority of Iraqis are Shia Arab Muslims (60%-70%), and Sunni Arab Muslims represent between 32% and 37% of the population. However, Sunni are split ethnically among Arabs, Kurds and Turkmen. Many Sunnis hotly dispute their minority status, including ex-Iraqi Ambassador Faruq Ziada, and many believe Shia majority is "a myth spread by America". One Sunni belief shared by Jordan's King Abdullah as well as his then Defense Minister Shaalan is that Shia numbers in Iraq were inflated by Iranian Shias crossing the border. Shia scholar Vali Nasr believes the election turnout in summer and December 2005 confirmed a strong Shia majority in Iraq.
Islam
A comprehensive 2015 demographic study of 232 countries and territories reported that 24% of the global population, or 1.8 billion people, are Muslims. Of those, it is estimated that over 75–90% are Sunni and 10–20% are Shia with a small minority belonging to other sects. Approximately 57 countries are Muslim-majority, and Arabs account for around 20% of all Muslims worldwide. The number of Muslims worldwide increased from 200 million in 1900 to 551 million in 1970, and tripled to 1.8 billion by 2015.