How would you explain the vast increase in christians, from 600 million in year 1910 to more than that, 800 million, now, of protestant alone?

the number of Christians in the world, has almost quadrupled from about 600 million in 1910 to more than 2 billion in 2020. Christianity remains the world's largest religious group.

800 million catching up to ancient hindus 900 m.
800 million catching up to ancient hindu's 900 m.

Despite the millions of europeans and Americans dying in 2 world wars... which reduced the total christians, yet the total multiplied.

and this increase was without any scary catholic inquisition, so how can we explain these incongruous facts?

Updates
1 mo
www.pewresearch.org/.../ explains the rate christian increase was GREATER than population increase , indicated real growth also the place was not Europe so truly spread. see there. not family as anonymous wrote here. different place and faster.
How would you explain the vast increase in christians, from 600 million in year 1910 to more than that, 800 million, now, of protestant alone?
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