By Dateline India Syndicate

Globally, Muslims have the highest fertility rate, an average of 3.1 children per woman – well above replacement level (2.1), the minimum typically needed to maintain a stable population. Christians are second, at 2.7 children per woman. Hindu fertility (2.4) is similar to the global average (2.5).

Worldwide, Jewish fertility (2.3 children per woman) also is above replacement level.

All the other groups have fertility levels too low to sustain their populations: folk religions (1.8 children per woman), other religions (1.7), the unaffiliated (1.7) and Buddhists (1.6).

Another important determinant of growth is the current age distribution of each religious group – whether its adherents are predominantly young, with their prime childbearing years still ahead, or older and largely past their childbearing years.

In 2010, more than a quarter of the world’s total population (27%) was under the age of 15. But an even higher percentage of Muslims (34%) and Hindus (30%) were younger than 15, while the share of Christians under 15 matched the global average (27%).

These bulging youth populations are among the reasons that Muslims are projected to grow faster than the world’s overall population and that Hindus and Christians are projected to roughly keep pace with worldwide population growth.

All the remaining groups have smaller-than-average youth populations, and many of them have disproportionately large numbers of adherents over the age of 59. For example, 11% of the world’s population was at least 60 years old in 2010. But fully 20% of Jews around the world are 60 or older, as are 15% of Buddhists, 14% of Christians, 14% of adherents of other religions (taken as a whole), 13% of the unaffiliated and 11% of adherents of folk religions. By contrast, just 7% of Muslims and 8% of Hindus are in this oldest age category. (DIS)