ST. PAUL, Minn.--(BUSINESS WIRE)--3M (NYSE:MMM) today reported second-quarter earnings of $2.02 per share, an increase of 5.8 percent versus the second quarter of 2014. Sales declined 5.5 percent year-on-year to $7.7 billion. Organic local-currency sales grew 1.8 percent and foreign currency translation reduced sales by 7.3 percent year-on-year. Operating income was $1.8 billion and operating income margins for the quarter were 23.9 percent, up 1.1 percentage points year-on-year. Second-quarter