Politico’s Michael Grunwald, among others, has been arguing that Obama’s Clean Power Plan is not actually as ambitious as some analysts make it out to be. The plan, which aims to cut emissions from the electric sector, is “pretty weak,” he argues, largely because emissions are already falling markedly. Today there’s a new data point to support that argument: Greenhouse gas emissions from U.S. power plants hit a 27-year low in April 2015, the most recent month for which data were available.

The Energy Information Administration, which tracks energy sector data as part of the Federal Statistical System, reported on Wednesday that the electric sector released 128.3 million metric tons of carbon dioxide into the atmosphere that month — the lowest since April 1988.

The EIA breaks down the numbers:

In any year, April is typically the month with the lowest carbon dioxide emissions from the electric power sector, mainly because of mild weather, as low heating and cooling demand are reflected in low overall electricity demand. Two fuels, coal and natural gas, account for almost all the carbon dioxide emissions from the electric power sector. In April 2015, electricity generation from both coal and natural gas fell from their March values, but because coal fell more than natural gas (18% versus 6%, respectively), generation from natural gas surpassed generation from coal in April. …

A longer historical perspective shows more significant changes in the electric power sector fuel mix. Comparing April 1988 to April 2015 (27 years), natural gas consumption in the sector more than tripled, renewable energy consumption more than doubled, nuclear energy consumption increased 47%, and coal consumption decreased 17%. Electricity generation has become less energy and carbon intensive over time. Compared to April 1998, April 2015 generation in the electric power sector was 44% higher, but the associated primary energy use and carbon dioxide emissions increased by only 33% and 4%, respectively.

See the visualization below to get a better sense of the emissions trend. (You can mouse over for monthly values.)

The EPA estimates the state-centric plan will cut emissions from the power sector by 32 percent of 2005 levels by 2030. As Grunwald and other analysts point out, power plant emissions have already fallen by about 15 percent since 2005, getting us halfway to the administration’s goal before the plan even kicks into gear.

Another notable low point from April 1988: Celine Dion pulled off a win at the Eurovision Song Contest for “Ne partez pas sans moi.”

See: