A new report from JPMorgan Chase’s research arm examined the deposit and spending patterns of 100,000 of its 27 million accounts during 2013 and 2014. It found that almost all the customers in the sample experienced changes in income and spending of 5 percent or more a month — not a tremendous fluctuation by any measure. But over the course of the year, 26 percent experienced income changes of 30 percent or more —10 percent suffered declines, while16 enjoyed increases. Income and consumption changes didn’t move in tandem. Just 28 percent of the survey subjects spent more money when they had more, and less when they had less.