Arizona political parties that appeared on the November 2008 ballot need registration of two-thirds of 1% by November 2009, in order to remain on the ballot for 2010. Arizona recently did a registration tally. The official results show that, currently, a party needs 20,587 registrations to meet the requirement. The Arizona Libertarian Party has been doing a registration drive, and the party now has 20,256 registrants, so it only needs another 331 registrants to meet the threshold, and there are six months to finish. However, the threshold is a moving target, and by the time November 2009 comes around, it will probably be slightly higher.
Arizona Libertarian registration in November 2008 was 18,153.
The Arizona Green Party now has 4,210 registrants.
If either the Libertarian or Green Parties had managed to poll 5% for president in November 2008, there would be no need for either party to have any particular number of registrants. The two-thirds of 1% registration test is an alternative to meeting the 5% vote test.