Around 93 percent of Azerbaijan's population is nominally Muslim, while about 5 percent of the population adheres to Russian Orthodox Church . Among the Muslim majority, religious observance is relatively low and Muslim identity tends to be based more on culture and ethnicity rather than religion; however, imams reported increased attendance at mosques during 2003.[who?] The Muslim population is approximately 70 percent Shi'a and 30 percent Sunni; differences traditionally have not been defined sharply.