If you paid any attention to the first day of the Republican National Convention, you likely heard this statistic cited over and over again from the stage: The GOP has gained more than 900 seats in state legislatures across the country since 2010.

That's absolutely right.

Here's a chart put together by Republican lobbyist Bruce Mehlman detailing the gains made by Republicans at the state legislative, gubernatorial and federal levels between the 2010 and the 2014 midterm elections.

Stunning, no? The 2014 election, in particular, saw a massive wave for Republicans at the state legislative level. Republicans gained 11 state legislative bodies in that election and after it controlled 68 out of 99 total chambers in the country. (Nebraska has a unicameral legislature.) "It is the most legislatures they have held in over 150 years, matching the previous high point after the 1920 election," noted Tim Storey of the National Conference of State Legislatures in the wake of the 2014 election.

And things have gotten even better for Republicans since then. In the most up-to-date numbers I could find, Republicans now control of 70 of the country's legislatures and have total control — state House, state Senate and governorship — in 24 states.

That massive down-ballot dominance — like lots of other good stories for the national Republican Party — have been totally drowned out by the rise of Donald Trump and the fissure within the GOP he either caused or contributed to.

It is these gains made over the past two elections that Republicans in the know are the most concerned about giving back if Trump loses badly to Hillary Clinton in the fall. These are races and places that get no national attention but form both the backbone of the GOP but also its political and policy incubator.

And that's why the gains Republicans have made are so important — and so important for the party not to give back wholesale in November.