About 90% of the population is Buddhist, with the majority of the rest being Muslims (mainly in South-Thailand and pockets in Bangkok). Christians are about 1.5% of the population, but active Protestant Christians just 0.5%. Because Christians are concentrated among the tribal groups, and to a lesser extent in the urban centers, the percentage of active Protestants in the countryside among the ethnic Thai is typically less than 0.1% of the population.
Yet there are encouraging signs for the church in Thailand. Two-thirds of all Protestant are first generation converts. The population of Thailand is growing 1% a year, but the number of Protestant Christians is growing about 5% a year. Thai people normally need a strong supportive Christian network, preferably relatives, before they will become Christian. So it is not easy to do pioneer evangelism in Thailand. However, Thai people from all walks of life are becoming Christians once this network is in place.
If you want to know more about the church in Thailand, how it grows, what kind of people are becoming Christians and how, and what kind of churches grow, read Marten Visser’s book Conversion Growth of Protestant Churches in Thailand.