A 2012 survey found that 36% of the world population is not religious and that between 2005 and 2012 world religiosity decreased by 9 percentage points. Being nonreligious is not necessarily equivalent to being an atheist or agnostic. A Pew Research Center global report in 2012 noted that many of the nonreligious actually have some religious beliefs. According to the study, "belief in God or a higher power is shared by 7% of Chinese unaffiliated adults, 30% of French unaffiliated adults and 68% of unaffiliated U.S. adults." The majority of the nonreligious (76%) are concentrated in Asia and the Pacific, while only a small portion comes from Europe (12%) or North America (5%).
Most Western democracies protect the freedom of religion, and it is largely implied in respective legal systems that those who do not believe or observe any religion are allowed freedom of thought.
A noted exception to ambiguity, explicitly allowing non-religion, is Article 36 of the Constitution of the People's Republic of China (as authored in 1982), which states that "No state organ, public organization or individual may compel citizens to believe in, or not to believe in, any religion; nor may they discriminate against citizens who believe in, or do not believe in, any religion." Article 46 of China’s 1978 Constitution was even more explicit, stating that "Citizens enjoy freedom to believe in religion and freedom not to believe in religion and to propagate atheism."
Although 10 countries listed below have non-religious majorities, it does not mean that majority of the populations of these countries don′t belong to any religious group. For example, 67.5% of the Swedish population belongs to Lutheran Christian Church, while 58.7% of Albanians declare themselves as Muslims. Also, though Scandinavian countries have among the highest measures of nonreligiosity and even atheism in Europe, 47% of atheists who live in those countries are still members of the national churches.
A Pew 2015 global projection study for religion and nonreligion, projects that between 2010 and 2050, there will some initial increases of the unaffiliated followed by a decline by 2050 due to lower global fertility rates among this demographic.  Sociologist Phil Zuckerman's global studies on atheism have indicated that global atheism may be in decline due to irreligious countries having the lowest birth rates in the world and religious countries having higher birth rates in general.
Gallup Religiosity Index 2009 (light color indicates religious, dark nonreligious)
The tables below order the percentage of a country's population that are nonreligious from highest to lowest.
^Zuckerman, Phil (2007). Martin, Michael, ed. The Cambridge Companion to Atheism. Cambridge Univ. Press. p. 59. ISBN0521603676.
^The Religiosity Index is a measure of the importance of religion for respondents and their self-reported attendance of religious services. For religions in which attendance at services is limited, care must be used in interpreting the data. (Gallup WorldView)[dead link]