The problem of explaining the relationship between wages in the nonunion sector and the wages negotiated in the union sector is another question that relates to the wage structure. Even though the employment share of union members has been declining, the wages of union members in the manufacturing sector have, in fact, achieved increases. 1 This recent experience continues to fuel the popular presumption that the wage structure is dominated by the institution of unions as opposed to market supply-and-demand forces. The extent of union impact on the relative wages of their membership is therefore a matter that warrants examination.