It’s useful context to look at the broad numbers:
Out of nearly 300 million Americans, 253.4 million (85%) have coverage, nearly 45.7 million (15%) do not. 202 million (67.5%) have private coverage: About 177.2 million (59%) have employer-based coverage, and a relatively small 26.7 million (9%) buy coverage as individuals. 83 million (28%) have coverage through public programs: 39.6 million (13%) have Medicaid, 41.3 million (14%) have Medicare, and 11 million (4%) have coverage through the military.
California’s uninsured rate inched up, to a 3-year average of 18.6%, up from 18.4% and 18.5% earlier in the decade. The Census figure pinpoints the number at 6.7 million uninsured. There are other figures, such as those from the California Health Interview Survey of the UCLA Center for Health Policy Research, which have different survey technique, and ask some different questions (Are you uninsured now? vs. Have you been uninsured in the past year?) Even with those differences, the Census data is important to indicate scale, trends, and baseline comparisons with other states.
Only six states have a higher percentage of uninsured residents than California: Texas, New Mexico, Florida, Arizona, Louisiana, and Mississippi.
The states with the lowest rate of uninsured are Massachusetts, Hawaii, and Minnesota, which suggests that state policy matters: you can you could look to the policies and reforms in the states to see how they have been able to reduce the uninsured rates.