The statistics in the previous page are from The Lausanne Statistics Task Force, cited in Grant R. Jeffrey Final Warning, Harvest House publishers, Eugene, Oregon, 1996, pages. 251-254. I have also heard of another edition of this book (probably the British edition) in which the relevant section is on pages 168-170.
Jeffrey also cites some of the statistics mentioned below this link.
From another source: International Daily News Bulletin No.245 [Original Source: Friday Fax]
According to missiologist Ralph Winter, only 1% of the world’s population had a personal relationship with Jesus Christ in 1430. Today, there are some 680 million evangelical Christians (11.1% of the world’s population) who started following Christ after a personal conversion. The rate of increase is around 7% per year, compared with around 2.6% for Islam.
Comment: I don’t know how the figure for Islam was calculated. I presume it refers to willing conversion, not forced by political takeovers of nations, etc.
For more, see, Truth, Stranger than Fiction