query: How many Christians are in the world?
passage: Christianity by country
As of the year 2015, Christianity has more than 2.3 billion adherents, out of about 7.5 billion people.[1][2][3][4][lower-alpha 1] The faith represents one-third of the world's population and is the largest religion in the world, with the three largest groups of Christians being the Catholic Church, Protestantism, and the Eastern Orthodox Church.[5] The largest Christian denomination is the Catholic Church, with 1.2 billion adherents.[6] The second largest Christian branch is either Protestantism (if it is considered a single group), or the Eastern Orthodox Church (if Protestants are considered to be divided into multiple denominations).
passage: Coptic Orthodox Church of Alexandria
There are about 20 million Coptic Orthodox Christians in the world. Between 15 and 18 million of them are found in Egypt under the jurisdiction of the Coptic Orthodox Church of Alexandria. Since Egypt does not have an official government census on religion, estimates of the size of Egypt's Christian population vary from the estimated low previous government figures of 6 to 7 million to the 12 million reported by some Christian leaders in 2008. The actual numbers may be in the 15 to 18 million range, out of an Egyptian population of more than 90 million. However, in 2011, the Pew Research Center announced that Copts in Egypt constitute 4.5% of the population, while the Catholic Holy See puts Copts at 6 to 8%. Then in 2017 government owned news Al Ahram estimated the percentage of Copts at 10 to 15%. However, in 2012 after the Egyptian revolution the Muslim Brotherhood was drafting new constitution then Major-General Abu Bakr al-Guindi claimed that the lower figures support a downward trend in the percentage of Copts in Egypt, as recorded in consecutive estimated Egyptian censuses since a 1927 high where Egyptian Christians formed 8.3% of the population. This decline has been explained by Major-General Abu Bakr al-Guindi, head of Egypt's Central Agency for Public Mobilization and Statistics, as being the result of Copts having the highest emigration rate, the lowest birthrate and the highest income level in the country. Although many Copts rejected this statement and population count by Abu Barker al-Guindi claiming they have been undercounted as most Copts reside in Upper Egypt.