This map shows the religion practiced by the majority of religious persons in the states of the world. It is pretty good. It does not depict non-religious populations. (For example, although recent surveys[1]archive copy at the Wayback Machine estimate that 43-54% of French, and 46-85% of Swedes self-identify as atheist, agnostic, or non-spriritual, those nations are depicted as Catholic, and Protestant, respectively.) If the ratio of the largest religious group to the next largest religious group is less than 60:40, then the color of the state is a blend of the colors of the two largest groups. Therefore:
Countries such as Lebanon receive a blend of of colors representing the two main religious groups i.e Christians and Muslims
States consisting of multiple nations, countries, or autonomous regions receive a single color determined by the aggregate of their inhabitants. Thus, Tibet, for example, receives the same color as the People's Republic of China, even though that color does not accurately describe the Vajrayana Buddhist religious affiliation of its inhabitants.
Persons without a religion (atheists) are not counted in determining the majority religion. Because of this, the Netherlands is colored steel-blue (mixed Protestant and Catholic), even though there are more non-religious people than there are Catholics, who constitute the largest religious group[2].
Regions within a state whose predominant religion is different from the plurality religion of the nation-state are not separately indicated. Thus, the southern islands of Mindanao, the Sulu archipelago and parts of Palawan which contain most of the Philippines small 5% to 10% Muslim population are painted Catholic pink. Russia is painted Orthodox purple because its officially small Muslim population who cluster around the Caucasus and Tatarstan at 5% to 6%, according to Russian state figures are not numerous enough to justify a mixed green-pink colour.
In Kazakhstan, Muslims (mostly Sunni) are generally estimated to form around 70% of the population while the large Christian minority (mostly Orthodox) consists of 26% of the population which justifies colouring this state a green in favour of Sunni Islam.
In Iraq, Shi'ite Muslims are generally estimated to form around 60% to 65% of the population while the large Sunni Muslim minority consists of 35% of the population and Christians only 3% which justifies colouring this state a light green in favour of Shi'ite Islam.
In contrast, Yemen is colored a mix of light dark green to reflect the fact that no religious group forms 60% of its population; the UNHCR[3] reports that its Shia Zaydi minority forms 45% of the population whereas Sunni Muslims comprise 53% of the population.
It is interesting to note that predominantly Hindu majority India--at 79.8%--according to the 2011 census has the second largest population of Muslims in any country of the world which stands at 14.2% of this state.
"Orthodox Christianity" on this map includes both branches that call themselves "Orthodox" (Eastern and Oriental). Thus, Armenia (Armenian Apostolic Church, an Oriental Orthodox denomination) is coloured the same as Georgia (Georgian Orthodox, an autocephalous Eastern Orthodox church).
I put Madagascar in blue (Protestant) because in Madagascar there are more Protestants than Catholics, but doing more research it turns out that Madagascar is actually almost equally divided between Catholics and Protestants.