Workers are not required to join a union on a given job. However, most sectors of activity with an average trade union organization of 70% are subject to a collective agreement. An agreement does not prohibit higher wages and better social benefits, but sets a legal minimum, much like a minimum wage. In addition, a national agreement on income policy is often, but not always, reached, including all trade unions, employers` organisations and the Finnish government.  Congress passed the National Labor Relations Act (NLRA) (29 U.S.) in 1935. C.A. § 151 et seq.) in order to define the right of workers to collective bargaining and other group activities (§ 157). The NLRA also created the National Labor Relations Board (NLRB), a federal authority empowered to uphold the right to collective bargaining (§153).