Asia, Europe, Africa, Latin America, and North America, with centers located in over 100 countries. Within the United States and Canada, Sukyo Mahikari has 21 spiritual development centers. Membership Sukyo Mahikari had approximately a million practitioners who form its membership as of 2011. Becoming a member of Sukyo Mahikari does not require giving up any preexisting beliefs or accepting Sukyo Mahikari as the only path or faith. Sukyo Mahikari teaches that the art of True Light and the universal principles transcend religious denominations and differences in ethnicity, nationality, and ideology. Sukyo Mahikari promotes cooperation and understanding between religious organizations toward establishing a sustainable and peaceful society. The emphasis the organization places on the spiritual unity of human beings has resulted in a membership that reflects a diversity of religions and nationalities. Sukyo Mahikari does not practice any form of tithe. The organization is sustained by the voluntary contributions (offerings) made by members. Rather than the amount, emphasis is placed on making offerings with sincerity. People are encouraged to make offerings that are voluntary and not beyond one's means. There are no mandatory contributions. However, there is a set amount for the appreciation offering to attend the introductory course and the spiritual cord maintenance offering. Members are encouraged to offer the monthly spiritual cord maintenance offering, which is approximately $7 in the U.S. and a similar amount in other regions. Cornille writes that there are a number of types of offerings in the organization: the spiritual cord maintenance offering; True Light appreciation offering; the special protection appreciation offering, and so on. Yoko Civilization Research Institute In 1985, Keishu Okada established the Yoko Civilization Research Institute (YCRI). The objective of the forum is to find solutions to today's problems by having leaders in different fields, regardless of their race, nationality, religion, and ideology, come together to share their acquired wisdom. 1st Yoko International Conference was held on Oct 30 to Nov 1, 1986. The theme was "Creating the future of mankind." 2nd Yoko International Conference was held on Oct 28 to Nov 1, 1989. The theme was "What does it mean to be human?" 3rd Yoko International Conference was held on Aug 18 to Aug 21, 1999. The theme was "Life and environment." 4th Yoko International Conference was held on September 18 to Sep 21, 2005. The theme was "Science and religion in the age of crisis." The 5th Yoko International Conference