On April 23, the California Secretary of State released new registration data, as of April 9, 2010. For a county-by-county breakdown, and state totals for each party, see here.
The previous registration tally had been as of January 5, 2010. Since then, the percentage of voters registered in the Democratic Party, and the Reform Party, has declined (the Reform Party is not ballot-qualified, but it is by far the largest unqualified party). Also, compared to January 5, the number of registered independents has declined. All the qualified parties except the Democratic Party increased their share.
This paragraph lists the qualified parties, with the January 2010 percentage first, and the April 2010 figure next:
Democratic: 44.62%, 44.57%
Republican: 30.75%; 30.79%
American Independent: 2.26%, 2.31%
Green: .659%, .664%
Libertarian: .499%, .506%
Peace & Freedom: .325%, .333%
Independents were 20.18% in January, and are now at 20.14%. Members of unqualified parties (including the Reform Party) were at .70% in January, and are now at .69%.