As you can see from this Michigan GOP primary poll line graph, a lot has happened since last September, none of it good for Ben Carson

Source:  Real Clear Politics

Recent state polls:
New Hampshire primary polls: One more day and then we move onto South Carolina and Nevada.  (2/8/2016)
Increasingly fewer Wisconsin GOP voters heed what Scott Walker sez.  (1/31/2016)
Trump, Cruz lose steam going into tomorrow's Iowa caucuses.  (1/31/2016)
Trump continues to rule the gamecock roost in South Carolina.  (1/30/2016)
Jeb Bush New Hampshire poll numbers: What goes up must come down.  (1/28/2016)
2 most recent Iowa caucus polls maintain candidates' separate trendlines.  (1/28/2016)
Cruz quickly closes the gap in North Carolina; Carson rides the slide.  (1/22/2016)
Trump more than doubles Rubio and Bush combined numbers in latest Florida Republican Presidential primary poll.  (1/20/2016)
FOX 5 Atlanta polls 97% white folks in latest Georgia Republican Presidential primary poll.  (1/18/2016)
Trump gets a little breathing room in latest Iowa poll; Rubio's stock flags.  (1/14/2016)
Ted Cruz leaps ahead of Donald Trump in latest California poll.  (1/6/2016)
Trump on top in Nevada.  (1/2/2016)
Chris Christie no favorite son in New Jersey; Donald Trump rules for now.  (11/18/2015)
Carson continues ascent in Virginia, Bush going the way of Scott Walker; Rubio bobs.  (11/18/2015)
Trump, Cruz on upswing; Carson, Bush on downslide in latest Texas Republican primary poll.  (11/12/2015)
As the polls churn in Arizona: Trump and Fiorina = big losers; Carson and Rubio = big winners.  (11/11/2015)

Scott Walker quickly flames out in Michigan.  (9/17/2015)