It's impossible to know exactly, but estimates are that about 5 billion people are religious, which is about 80% of the world, the number is declining rapidly especially in developing countries such as China. Most of those are Christian, Muslim, or Hindu.
According to Adherents.com most people on the planet practice a religion (or two) of some sort. Adherents gives the following numbers taken from a variety of sources which they define as being:
[The] major source for these estimates is the detailed country-by-country analysis done by David B. Barrett's religious statistics organization, whose data are published in the Encyclopedia Britannica (including annual updates and yearbooks) and also in theWorld Christian Encyclopedia (the latest edition of which - published in 2001 - has been consulted). Hundreds of additional sources providing more thorough and detailed research about individual religious groups have also been consulted.
Their figures are:
nearly 15,000 people attended the festivals each yearIt began in the religious festivals that honored Dionysus, the Greek god of wine.
Jewish; or religious Jews.
There are by 2001 estimates, 159,030,000 Christians in the United States. (Source: American Religious Identity Survey)
Left mostly for religious freedom.
A religious cult could be considered a form of deviant behavior. Many religious cults defy norms that have been set forth by society.
Religious people? About 6 billion.
many people support religious freedom.
There are people's of many traditions in a country. Division of people on the basis of religion, cast, etc is religious divide
There are many ways to get a religious education. Many people are self taught through research in libraries and book stores. Also, many universities offer religious degrees.
many religious people say that God is our Almighty god and that he is the son, the father and the holy spirit
Because Mexicans are a deeply religious people, and as such, there is a large amount of religious -- mostly Catholic -- schools in Mexico.
About 900 million.
Beliefs in many gods
The people there have many different religions.
Many, millions even, have allegedly died in the wake of religious causes.
Religious people perform religious rites.
Genesis seems to impact our culture today by creating a divide between people who believe in creationism and people who believe in evolution. This divide angers many people who are religious and many who are not religious.