There is some interesting demographic data on the growth of Christianity.
"Within the next twenty-five years the population of the world's Christians is expected to grow to 2.6 billion (making Christianity by far the world's largest faith). Stop and consider that: it will grow by 2.6 billion. From 1934-1994, the number of Christians in the world increased by 1300 percent (from 40 million to 540 million in the last 60 years), while the world's population grew only 400 percent.
But this growth has largely taken place in the Southern hemisphere and in Asia, outside the radar of most Western media. Of the approximately two billion Christians alive today (one-third of the planetary population), 560 million live in Europe and 260 in North America, for a total of 820 million. The combined number of Christians in Latin America (480 million), Africa (360 million), and Asia (313 million) is 1.15 billion. On a percentage basis, then, almost 60 percent of Christians in the world today live in the Third World. Jenkins forecasts that of the expected 2.6 billion Christians in the year 2025, 67 percent will live in Africa (633 million), Asia (640 million), or Latin America (460 million). Jenkins emphasizes that by 2050 only about one-fifth of the world's three billion Christians will be non-Hispanic whites. As Jenkins states: "Soon the phrase 'a White Christian' may sound like a curious oxymoron, as mildly surprising as 'a Swedish Buddhist.' Such people can exist, but a slight eccentricity is implied." "
Oddly, this geographic growth pattern seems inversely related to the number of Christian bookstores and radio stations.