I read the story to mean more than half of all Mormons will be Latino; not that half of all Central Americans will be Mormon.
Well, if that’s the case you could be correct.
The story said:
If the Mormon Church continues to grow at current rates, it will be majority Latin American by 2015.
For what it’s worth, the Mormons in Mexico and in Central America are largely empty buildings. They really don’t have much to brag about. If they get adherents, people are going for the THINGS that the Mormon church has to offer them, a Marriage in Heaven, or some financial help to get buy. Not many are converting to their book of Joseph Smith