I snapped the above picture in Cairo, Egypt last year.  To the left is a Coptic Orthodox Church and to the (right) is a fabric store with writing in Arabic.  I was on a reconnaissance mission to figure out what it would take Muslims to become Christian and what it would take to get non-Catholic Christians to become Catholic. My findings were reflected in some recent secular studies:

The Pew Research Center recently reported:  “Christians remained the world’s biggest religious group. But Christians (of all denominations, counted as one group) did not keep pace with global population growth from 2010 to 2020. The number of Christians rose by 122 million, reaching 2.3 billion. Yet, as a share of the world’s population, Christians fell 1.8 percentage points, to 28.8%.”

The Washington Post also covered the above stats: “Even as the overall number of Christians — counted as one group, across denominations — continued to climb to 2.3 billion, the religion’s share of the world’s population decreased by 1.8 percentage points to 28.8 percent, a falloff driven in large part by disaffiliation. The Muslim population, on the other hand, increased by 1.8 percentage points to 25.6 percent, according to the report, which examined changes in religious demographics through an analysis of more than 2,700 censuses and surveys.”…