How come some countries do not have teen pregnancies?

i check and it seems that sri lanka has no teen pregnancy recorded during the last 10 years. very few sri labkans even know that their is such a thing as teen prgnancy. just google it and see. i find this unbelievable. how do they do it? i guess there are others countries like this too but i have only heard of sri lanka.what i wanna know is how do these people do it? i mean have no teen pregnancy at all?