The number of Christians around the world has nearly quadrupled in the last 100 years, from about 600 million in 1910 to more than 2 billion in 2010. But the world’s overall population also has risen rapidly, from an estimated 1.8 billion in 1910 to 6.9 billion in 2010. As a result, Christians make up about the same portion of the world’s population today (32%) as they did a century ago (35%).
