In less than a decade, the worldwide population of Christians is expected to reach 2.6 billion, according to a new study.

The study, titled "Christianity In Its Global Context, 1970-2010," and conducted by the Center for the Study of Global Christianity at Gordon Conwell Theological Seminary in Massachusetts, examined trends since 1970 and predicted how the numbers are likely to change in 2020.

In 1970, 1.2 billion people were Christians out of a total population of 3.7 billion. By 2020, there are expected to be 7.7 billion total inhabitants of the planet.

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The rate of Christian growth has slowed significantly, from 33.2 percent in 1970 to 1.47 percent projected for 2020. The majority of current growth is in Africa, South America and Oceania, which includes Australia and surrounding islands. Asia is seeing the highest percentage of growth, though Christianity remains a minority religion there.

Christianity is declining in Europe and North America, mostly through people abandoning religion for atheism or agnosticism and from the birth rate not keeping up with the death rate.

But despite atheists becoming more outspoken in recent years, their numbers as a percentage of population is declining. The same is true of agnostics.

The study looked at all religions and at atheism and agnosticism. The full report can be found at the Gordon Conwell website.