Europe is shrinking but the majority of Christians live outside of Europe. The Catholic Church has grown by 121 million souls from 2000 to 2009.http://www.rte.ie/news/2010/0428/catholic.html
Why do you think Catholics are so sure of themselves when we speak to Orthodox? Our church is growing!
121 million sounds like a lot (and it is, to be sure), and that is an 11.5% increase, the article says. But the world's population increased by 11.3% in that same time period, so the RCC's growth rate was only 0.2% faster than the overall population growth.
The rate of increase over population is 10% in Africa and 6% in Asia, flat in the Americas and Oceania, and a 2% decline rate in Europe.
(Population data from: http://www.census.gov/ipc/www/idb/region.php
It would be interesting to have figures for the same period for EOC, OOC, and various Protestant groups.