Slow gradual decline.
http://www.thegatewaypundit.com/2016/04/simply-worst-obama-f...
Have a look here:
http://www.tradingeconomics.com/united-states/gdp-growth-ann...
choose "trend line". You'll see that 2015/2016 GDP growth is precisely on the trend line. The main difference in the last 8 years is more stable GDP growth, rather than the extreme peaks and troughs of the previous 60 years.
I live in Canada and don't have a dog in this race, but I find it interesting that Americans are so obvlivious of the facts and willing to believe at face value all the BS that comes out of the likes of Trump.