A meeting of the association must be held at least once each year. A special meeting of the association may be called by the president, by a majority of the members of the executive board, or by unit owners comprising either 20 percent or a lower percentage specified in the bylaws of the votes in the association. Not less than 10 nor more than 60 days in advance of a meeting, the secretary or other officer specified in the bylaws shall cause notice to be hand-delivered or sent prepaid by United States mail to the mailing address of each unit or to the mailing address designated in writing by the unit owner. The notice of a meeting must state the time and place of the meeting and the items on the agenda, including the general nature of a proposed amendment to the declaration or bylaws, budget changes, and a proposal to remove an officer or member of the executive board.