What a difference a year makes — especially when you spend the first portion of it working on a policy at odds with your base.

Florida Sen. Marco Rubio lost 12 percentage points in 12 months, according to an analysis of national Republican primary polling in 2013.

That’s the most significant change in support over a year of all the potential 2016 contenders.

The RUN looked at national polling in 2013 — compiled by HUFFPOST Pollster — to compare where the top Republican candidates stood during the first three months of the year compared to the final three months of the year.

Whereas Rubio was averaging about 20 percentage points in national GOP primary polls between January and March, that number plummeted to only about eight percentage points between October and December.

FIRST THREE MONTHS 2013:

Rubio: 19.6

Christie: 12.5

Paul: 7.6

Cruz: Not polled

New Jersey Gov. Chris Christie was polling at about 12 points, whereas Kentucky Sen. Rand Paul averaged eight percentage points to start the year.  Texas Sen. Ted Cruz wasn’t included in a national GOP primary poll until May — when Public Policy Polling pegged him at seven percent.

During the last three months of the year, Christie had increased his share to 17 points and Paul sat at an 11 point average.  Cruz shot all the way from not being included in surveys to 12 points.

LAST THREE MONTHS OF 2013:

Christie: 17.2

Cruz: 12.4

Paul: 11

Rubio: 7.6

While Christie ends the year as the solidified polling front-runner, it’s Cruz who gained the most over the last twelve months.  And as the data demonstrates, it’s Rubio who lost the most.

Numbers from the first three months were based on averages of eight national polls; numbers from the final three months included nine.

Follow Dave’s blog at TheRun2016.com