the statistics you cite are sort of misleading. First there are 1.5 billion Catholics, but to reach that number you must include Eastern & Oriental Orthodox Catholics (at this point there are perhaps less than a billion Roman rite Catholics … though the way Rome formulates its numbers, i.e. the body count method, is hardly a sound methodology … but that’s another thread topic I suppose). Secondly, when you say vocations are way up in Africa and Asia, why should this surprise anyone? Shelter, clothing, and three meals a day will pretty much ensure a steady supply of priests in the poverty stricken, third world havens of Africa and Asia.
Along with these facts it’s important to note the fastest growing sect within Christianity is the Pentecostal denomination. Not something I’m overly pleased with (since I’m Presbyterian) … but it’s a fact. Although I disagree (strongly) with Pentecostals, since I believe nothing happens without the will of God concerned, I know there is some reason God has ordained the growth of Pentecostalism in places like Africa. Perhaps the Pentecostals can sweep them in with their very emotive worship practices & we can lead them towards a firm theological foundation down the road?