Investing.com - With the nation's unemployment rate at a 17-year low, more companies are encountering labor shortages and resorting to wage increases, according to a closely watched survey of corporate economists.The April survey of the National Association of Business Economists found 45% of those companies surveyed faced a shortage of skilled labor--the highest reading in a decade. Slightly more than a third said they had raised wages as a result. NABE's index for wages and salaries rose to its highest level in the survey's 25-year history.Washington policy changes, however, have had little impact on companies' business decisions. The survey found than more than six out of ten companies did not change their hiring or investment plans because of either the corporate tax cut or the steel and aluminum tariffs.