The country has an area of 35,919 square miles and a population of 10.1 million. Data on religious affiliation is regarded as sensitive information and may not be officially recorded. However, the 2001 national census, the latest survey available, included an optional question on religious affiliation, to which 90 percent of the population provided a response. According to the replies, the population is 55 percent Roman Catholic, 15 percent Hungarian Reformed, 3 percent Lutheran, and less than 1 percent Jewish. These four are the country's "historical" religious groups. In addition, 3 percent of respondents identified themselves as Greek Catholics, and 15 percent declared no religious affiliation. Groups that constitute less than 5 percent of the population include the Congregation of Faith, a broad range of other Christian groups, five Orthodox Christian religious groups, seven Buddhist groups, and three Islamic communities.
Data protection regulations impede the collection of official statistics on popular participation in religious life; however, surveys suggest that citizens are less devout than the average central European. In a 2004 survey by the Economic Research Institute of Hungary, 58 percent of respondents declared themselves to be "believers," and 55 percent responded that they believe in "God or the supernatural." Fifteen percent of believers declared that they attended religious services at least once a week, and 25 percent stated that they never did.