For some time I had this idea in mind, and now that I spared a couple of hours I put it into practice. I wanted to create a map about religious diversity, showing how most of the people in the world choose their religion (actually they are assigned their religion at birth) according to their family and country, and not according to faith.
For me it is quite obvious and it wouldn't need a map, but for many people unfortunately it's not. I found always quite funny the idea that 100 meters before a border there are 90% Catholics, and just 100 meters after 90% Muslims, and quite humorous (thought extremely sad) to think that wars, political parties, and people in general are fighting according to believes that they didn't even choose themselves.
My map about Religious diversity doesn't want to be anything close to scientific, and there might even be some mistakes in the color, since I didn't review all the countries. It was just to put an idea into a map and take a break from my duties.
I used as a source the data from the CIA report "The World Factbook" and when the percentage was not written, I searched for the country on Wikipedia. If also there there were no details, then I classified the country as "No data".
There were also a few countries were the official data were different than the reality (just think of China, North Korea and Russia to name a few), but I still classified them according to my 2 sources. Also it looks like the CIA used mixed data itself, mostly taken from the latest census, but sometimes just estimates, possibly far from reality. Other times there were differences between practicing and non-practicing worshipers, but mostly not.
The red color is denoting countries where one single sub group (I haven't written religion, because I would consider subgroup also atheist) was over 60% of the population. With subgroup I mean Christian Catholics, Christian Orthodox, Muslim Sunni, etc. When the percentage was below 60%, I checked if the whole group (in example Catholics + Protestant + Orthodox) were over 60%. This is the second group with the lighter red color. All the rest was marked with a blue color. So basically there are just a few countries (in the world) where there is no predominant religious group with a percentage superior to 60%.
This still doesn't mean that in the country with the blue country people are more aware of their religion, it might just mean that religion has been more diverse for long time, and now it is passed from generation to generation.
Maybe it would be interesting also to do a different map according to the percentage of people that change their religion in each country.