Each year the Center for the Study of Global Christianity publishes the Status of Global Christianity.
A few highlights via Facts&Trends:
Christianity is growing faster than the world’s population (1.27% vs 1.20%), but Islam is growing even faster (1.95%) and could overtake Christianity as the worlds’ largest religion by 2050.
Evangelicals (2.19%) and Pentecostals (2.26%) are the fastest growing forms of Christianity.
Atheism is declining. There are fewer atheists in the world today (138 million) than there were in 1970 (165 million).
Christianity is exploding in Asia (1.89%) and Africa (2.89%) compared to Europe (0.04%) and the US (0.56%).
The percentage of the world considered unevangelized has decreased from 54.3% in 1900 to 28.4% today. That still means that almost 2.2 billion people living today are unevangelized.