How has the share of No Party Preference (independent) voters in California changed since 2000?
Executive summary
No Party Preference (NPP) — formerly “Decline to State” — rose sharply in California from the 2000s through the 2010s and by 2018 had become the state’s second-largest registration group, but recent reports through 2025 show that its share has flattened or edged down to roughly 22–23% of registered voters (e.g., 22.34% in Feb. 2025) [1] [2] [3]. Available sources document the long-term rise driven largely by new registrants and demographic change, then a leveling and modest decline since about 2019–2021 [4] [5] [3].
1. The big arc: from small minority to second-largest group
California’s NPP cohort grew from a relatively small “decline to state” group after the modified primary rules of 2000 into a major bloc by the late 2010s; the Secretary of State highlighted that by May 2018 NPP was the second-largest registration group in the state, reflecting years of steady gains [1]. Analysis from the Public Policy Institute of California and related research traces much of that growth to new registrants arriving in the state or first-time registrants choosing no party preference [4].
2. Why it grew: new registrants and changing registration choices
PPIC and its collaborators found that new registrants since the early 2010s disproportionately chose NPP or minor parties rather than Republican, with roughly 3.5 million new voters registering as “some other party or NPP” versus 1.8 million as Republicans in the period analyzed — a dynamic that fueled the NPP rise [4]. The Secretary of State’s materials and county guides emphasize that the “modified” closed primary instituted around 2000 changed incentives for non-affiliated registration and that NPP voters can, in some cases, participate in party primaries if parties choose to allow them [6] [7].
3. The turning point: flattening and modest decline since about 2019–2021
Reporting and state registration snapshots indicate the NPP share began to plateau and then shrink modestly around the 2019–2024 period. Local reporting in 2023 flagged that NPP registrations were shrinking while both major parties were regaining ground since 2019 [5]. Official registration reports through February 2025 record a slight decrease in the NPP percentage — from 22.48% to 22.34% in the latest odd‑year report — and PPIC’s 2025 profile places NPP at about 22.3%, down from 23.7% in 2021 [2] [3].
4. How big is the change numerically?
Sources give percentage points rather than a clean year‑by‑year time series in these excerpts. Key figures reported: NPP reached the state’s second‑largest group by 2018 [1]; PPIC measured NPP at 23.7% in 2021 falling to 22.3% by mid‑2025 [3]; the Secretary of State’s February 2025 material notes a decline from 22.48% to 22.34% between two odd‑year reports [2]. These datapoints show growth through the 2000s–2010s and a modest recent retreat of roughly 1–2 percentage points from peak levels cited in different sources.
5. Competing interpretations and the limits of the public evidence
Researchers attribute the earlier rise chiefly to new registrants’ preferences and demographic turnover [4], while 2023–2025 coverage frames the recent shrinkage as rising partisanship and re‑affiliation with major parties [5] [3]. Available sources do not provide a complete, single-year annual series back to 2000 in these excerpts, so precise year‑by‑year percentage changes since 2000 are not provided here; for a full historical table, the California Secretary of State’s registration statistics page would be the primary repository [8], though that detailed table is not reproduced in the provided excerpts.
6. Why this matters politically
NPP voters affect primary dynamics because California’s “modified” closed primary and later open/nonpartisan blanket primary rules changed how non‑affiliated voters can participate in primaries — parties may allow NPP voters to request their ballot, and the evolving NPP share alters turnout and nomination outcomes [6] [7]. The growth of NPP through the 2010s was a structural shift in the electorate [4]; even a modest decline since 2019–2025 could change strategic calculations for parties and candidates in both primaries and general elections [5] [3].
7. Bottom line and where to look next
Bottom line: NPP rose substantially from the 2000s into the 2010s to become a major registration category by 2018, then flattened and has edged down to roughly 22–23% by early–mid 2025 [1] [4] [2] [3]. For an exact annual time series and county‑level trends since 2000, consult the Secretary of State’s full voter registration statistics and historical reports [8].