The phrase "decade increase" refers to a growth or rise in something over a period of ten years. It means that a certain quantity or value has gone up or improved significantly within that specific time frame.
While prior growth was at 1.9 m tons per year, this next decades increase would mean a growth of approximately 1.4 m tons per year. (dairyreporter.com)
Consistent with earlier research, six of the top 10 states with the biggest increases in number of days with heavy downpours are in the Northeast, including Rhode Island, Maine, and New Hampshire, which have seen the number of heavy rain events in the last decade increase by at least 50 percent compared to the 1950s. (climatecentral.org)