California’s unionized workforce grew 3 percent last year, according to new federal labor data that also show more employees in both the government and private sectors nationwide worked under labor-negotiated terms. Of California’s 15.13 million workers, 2.65 million were represented by a labor union in 2014, about 73,000 more than the year before. The figures include dues-paying union members and non-members whose jobs were covered by a labor agreement.