Statistics are useful but they don't always show accurate information. India is one of the most diverse country in the world. Hell even the states are like little countries living together. I am an Indian but even I can't make assumption like that about another state.

But still I don't think everyone replaces their phones in just 3 years. The younger generation does that (they replace their phones even faster). But the older generation who use a smart phone like a phone keeps their phones for lot more then 5 years.

And these days due to population control awareness most couples limit themselves to only 2 children.