I just came back from visiting family in South America (will keep the name of the country out for now) and I was shocked by the amount of JWs I saw on the street. Keep in mind that most countries in SA have been under military rule until the early 80s, with the general fear and mindset sticking around until the late 90s, even when the military was gone and democracy re established. JW were not around when I lived there. The last time I visited in 2011, there were few congregations and there was none but a single JW in my town. There seems to have been tremendous growth since then because now they seem to be everywhere. Like everything that is new, it has a lot of synergy. There was not one day we went downtown where we did not see a JW on the street, no matter what time of the day. No matter which part of the country we went to, the same happened.
There has to be a whole lot of people leaving the org in order for such growth to be diminished worldwide.