I did, You may have conflated growth due to a high birthrate with a growth due to conversion. Worldwide when it comes to conversion Christianity has lost far more than they have gained:
Christian population growth - Wikipedia
According to
Pew Research religious switching is projected to have a modest impact on changes in the Christian population. According to a study by the Pew Research Center, it is expected to convert to Christianity 40,060,000 persons, while leaving Christianity 106,110,000 persons, thus, it is a net loss for Christianity nearly 66,050,000 between 2010 and 2050, and according to the same study, Christianity is expected to have the largest net loses through religious conversion.
[4][10]
One has to be careful of one's sources because they will often cherry pick. When it comes to conversion from another religion Christianity seems to lead the way, but that is still a much smaller number than its losses:
According to the
World Christian Encyclopedia, approximately 2.7 million convert to
Christianity annually from another religion;
World Christian Encyclopedia also stated that Christianity ranks in first place in net gains through religious conversion.
[5] While, according to book "The Oxford Handbook of Religious Conversion", which published by the professor of
Christian mission Charles E. Farhadian,
[11] and the professor of
psychology Lewis Ray Rambo,
[12] between 1990 and 2000, approximately 1.9 million people converted to Christianity from another religion, with Christianity ranking first in net gains through religious conversion.
[13] According to "The Oxford Handbook of Religious Conversion", in mid-2005 approximately 15.5 million convert to Christianity from another religion, approximately 11.7 million leave Christianity, and most of them become irreligious, resulting in a net gain of 3.8 million.
[6]
But you are right about growth being high in Latin America, but that is probably due to population growth. It is clearly not conversion:
Christianity adds about 65.1 million people due to factors such as birth rate and religious conversion, while losing 27.4 million people due to factors such as death rate and religious apostasy in mid-2005. Most of the net growth in the numbers of Christians is in Africa, Latin America and Asia.
[6]