Membership in the credit union is voluntary and is open to all citizens bound by with joint work or residence, who wished to create a credit union to use its services and are willing to take on relevant commitments and responsibilities. In the U.S., credit unions have a clear organizational structure. All credit unions belong to one or the other parent credit union (there are 35 of them in the U.S.). Like the credit cooperatives, credit unions form associations of a higher level, which are called corporate credit unions. Members of credit unions place in credit unions usually free fund balances, ie those that remain after expenses devoted to education of children, the acquisition of new properties, additional pension benefits, etc. National Credit Union Insurance Fund was created by Congress in 1970 to insure deposits of credit union members in the amount of 100 thousand dollars.