(CNN) Both Donald Trump and Barack Obama enjoyed unified government for their first eight months as president -- but one-party control hasn't meant the same thing in 2017 as it did in 2009.

Single-party rule in the United States has been rare in the last few decades: This is only the fifth time it's happened since 1980 -- giving Republicans a rare opportunity to advance major policy initiatives without needing Democratic support.

But in the first eight months under Trump, progress has stalled. Major GOP goals like health care reform and simplifying the tax code have not yet come to pass.

A CNN analysis of new legislation and votes by Congress in the first eight months of the last several unified governments shows the 2017 government more on par with President George W. Bush's government in 2003 and President Bill Clinton's coalition in 1993 than Obama's government just eight years ago.

Of course, this way of measuring results isn't perfect. Some bills rename post offices and others spend billions of dollars. Some short bills can be far more influential than ones that span hundreds of pages. And some votes pass major legislation while others are just routine housekeeping.

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