And note they always just "suspend" and not actually declare an end to their campaign. That is so they can still fundraise- either to pay off campaign debt or to help fund other future campaigns (in Rand Paul's case his re-election bid).
It is basically a five person race right now- Trump, Cruz, Rubio, Bush, and Kasich. Bush looks weak(compared to his family results to date) but not weak enough to drop out. He has been below five percent nationally since December. Trump's numbers have declined a bit lately- he was about 35% nationally and is now down below 30%. Meanwhile Rubio has gone from ten percent to 17.8%.
Real race is Rubio. Cruz, and Trump.