By Aaron Kessler and Annie Grayer, CNN

(CNN) -- Early voting ahead of the midterm elections continues to skyrocket.

Based on data provided by Catalist, a data company that works with Democrats and others to compile these counts of early ballots cast before Election Day, either in person or by mail, at least 12 states have already surpassed where their early voting numbers were in 2014. Two states have just outpaced their early voting at this point in the 2016 presidential election: Kansas by almost 25,000 votes and West Virginia by over 1,000 votes. This could signal voter excitement this year, but it also tracks with a general move toward early voting in the US.

First time voters

The percentage of early voters that are first time voters is substantial.

Of the states for which Catalist has provided data to CNN, first-time voters have cast 5% or more of the early vote in 10 states.

Although this data is not compared with first time voters of cycles past, it is helpful to get a snapshot of newly participating voters this cycle.

It is expected that the share of first-time registrants among the 18 to 21 age group bracket would be substantial, given many in that group were not old enough to vote in a previous election.

But the CNN analysis found a notable portion of first-time voters this cycle are in their 20s and 30s.

In Nevada, over 10% of the early voting electorate are first-time voters.

Among those 22-29 years old, 13% are first-timers, and among voters 30-39 years old, 10% are newly registered.

North Dakota also has a high percentage of first-time voters from a wide range of ages. Ten percent of all early voters are registered for the first time. Among those 22-29 years old, more than a quarter are first-timers. For early voters 30-39 years old, first-timers make up 17% of the early voters.

Seven percent of Arizona's early voting population are first time voters. Twelve percent of voters 22-29 years old are new, and among those 30-39 years old, 8% are newly registered.

Arizona, Montana, Texas, Tennessee, Georgia and Florida all have groups of first-time voters that hover around or higher than five percent.

Early voting in competitive House districts

Going a step closer, CNN also analyzed Catalist data to determine the share of first-time voters in several key House races.

In the Texas 7th District, which is a Tossup in CNN's Key Race ratings, and where Republican Rep. John Culberson faces off against Democrat Lizzie Pannill Fletcher, nearly 9% of all early voters 22-29 years old are registered for the first time. Another 6% of those in their 30s are new. By contrast, senior voters in the district ages 65 and up have barely above 1% of their ranks being new to the game.

In the hotly contested Texas 23rd, a Lean Republican district where Republican and CIA veteran Rep. Will Hurd is battling Iraq War veteran and Democrat Gina Ortiz Jones, the same pattern is evident. Nearly 8% of those between 22-29 years old are newly registered, and for those in their 30s, it's 6%. For seniors 65 and up? Less than 2% are new.

In the fight for the open seat in Florida's 15th District, a Tossup, about 7% of voters are between 22-29 years old are first-timers. That compares to senior citizens 65 and up, where only 2% are first-timers.

The same proportion of 22-29 year olds are first time registrants in Florida's 27th District, while there seniors make up less than 2% of new voters.

Other key races are more mixed. Only about 3% of those 22-29 years old are new in the New Jersey 3rd, another Tossup, and only slightly more among those in their 30s.