A new Washington Department of Ecology inventory shows greenhouse gas emissions spiked about 6.1 percent from 2012-2015, due in part to increasing fossil-fuel-generated electricity and a booming economy.

The state sent more than 97 million metric tons of greenhouses gases into the atmosphere in 2015, compared with 90 million in 1990.

The Seattle Times reports that although emissions are rising, the 2015 figure represents progress from the year 2000, when emissions topped out at nearly 109 million metric tons.

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The report quantified total emissions using U.S. Environmental Protection Agency data and information from the Washington state Department of Commerce. Transportation was responsible for more than 42 percent of total emissions, according to the report.

Washington legislators a decade ago wrote into law a plan to reduce greenhouse gas emissions to 1990 levels by the year 2020.