A recent study by Professor Michael McDonald at George Mason University showed that the major political parties in Oregon (Democratic and Republican) have lost since November 2008 a greater share of their members than the major parties in any other state, except Nevada.

The results are here: http://www.huffingtonpost.com/michael-p-mcdonald/partisan-voter-registra...

The Oregon Democratic Party has lost 7.1% of its members since then. The Oregon Republican Party has lost 5.2% of its members during that period.

On the other hand, the Independent Party of Oregon has increased its membership by 44% since November (from 42,008 to 60,596 as of September 2010).

Numerically, the Democrats have lost 66,755 members in Oregon since November 2008. The Republicans have lost 33,921 members. Overall voter registration in Oregon since November 2008 has fallen by 91,656.