The Colorado Secretary of State has posted the July 1, 2017 voter registration data. The percentages for each party are: Democratic 31.49%; Republican 31.25%; Libertarian 1.18%; Green .34%; Constitution .32%; Unity .03%; independents and others 35.40%.
In November 2016, the percentages were: Democratic 31.80%; Republican 31.51%; Libertarian 1.16%; Green .35%; Constitution .30%; Unity .02%; independents and others 34.86%.
Colorado also posts partisan data for its inactive voters.
The percentages per party are: Democratic 25.84% (27.61% in November 2016); Republican 24.14% (24.75%); Libertarian 1.34% (1.16%); Green 0.52% (0.49%); Constitution 0.41% (0.37%); Unity 0.04% (0.02%); unaffiliated 47.71% (45.60%).
The number of inactive voters declined from 550,676 to 361,812 since the December 1, 2016 report, reflecting voters who did not vote in 2014 and 2016, and whom apparently no longer reside at their registration address. “Inactive voter” is somewhat of a misnomer. A voter is listed as “inactive” if they can’t be contacted by mail. They are purged if they don’t vote in either of the following two federal elections. Inactive voters purged this year had already been removed from active rolls. So the changes in 2017 for active voters reflect mostly new registrations minus voters who are confirmed to have died or moved out of state.
Inactive voters appear to decline during election years. This is likely due to voters re-registering at a new address. When this happens, their old inactive registration at a previous address is cancelled.
The number of inactive voters has declined precipitously in Colorado (75% decline since 2010). Some of this may reflect recovery from the recession, as persons who were upside down on a mortgage or out of a job may have left the state or moved in with parents or other relatives. Some of these persons might have deliberately left no forwarding address.
But the size of the decrease in inactive voters suggest other changes in tracking voters. Perhaps increasing use of all-mail elections has resulted in election officials more continuously tracking addresses, and voters being aware that they should update their address if they wanted to receive a ballot.