For anyone who wants to research voter registration data for the contested states.
Arizona November 2020 https://azsos.gov/sites/default/files/State_Voter_Registration_2020_General.pdfNovember 2016 https://apps.azsos.gov/election/2016/General/Official%20Signed%20State%20Canvass.pdf page 1 November 2012 https://apps.azsos.gov/election/2012/General/Canvass2012GE.pdf page 1 November 2008 https://apps.azsos.gov/election/2008/General/Canvass2008GE.pdf page 1 November 2004 https://apps.azsos.gov/election/2004/General/Canvass2004General.pdf page 1 November 2000 https://apps.azsos.gov/election/2000/General/Canvass2000GE.pdf page 1
Georgia November 2020 https://sos.ga.gov/admin/uploads/Active_Voters_by_Race_Gender_as_of_November_1_2020.xlsxHistorical https://sos.ga.gov/admin/files/Voter%20Registration%20Statistics%20Historical%20-%20Updated%2011-26-18.pdf not at county level
Michigan (all the months are in the same file) 2020 Voter Registration Totals https://www.michigan.gov/documents/sos/2020_Registered_Voter_Count_682262_7.pdf2016 Voter Registration Totals https://www.michigan.gov/documents/sos/2016_RegVoterCount_511666_7.pdf2012 Voter Registration Totalshttps://www.michigan.gov/documents/sos/2012_voter_reg_totals_376923_7.pdf2008 Voter Registration Totals https://www.michigan.gov/documents/sos/Voter_Regis_Total_by_County_316983_7.pdf2004 Voter Registration Totals https://www.michigan.gov/sos/0,4670,7-127-1633_8722-97959--,00.html2000 Voter Registration Totals https://www.michigan.gov/sos/0,4670,7-127-1633_8722-31523--,00.html
Minnesota Registered Voters by County as of November 2, 2020 https://www.sos.state.mn.us/election-administration-campaigns/data-maps/voter-registration-counts/Voter Registration since 2000 https://www.sos.state.mn.us/media/3294/minnesota-voter-registration-by-county-since-2000.xlsx
Nevada October 2020 https://www.nvsos.gov/sos/home/showdocument?id=9110November 2016 https://www.nvsos.gov/sos/home/showdocument?id=4591November 2012 https://www.nvsos.gov/sos/home/showdocument?id=2559November 2008 https://www.nvsos.gov/SOSElectionPages/voter-reg/2008/1108maint.aspxNovember 2004 https://www.nvsos.gov/SOSElectionPages/voter-reg/2004/1104main.aspxNovember 2000 https://www.nvsos.gov/SOSElectionPages/voter-reg/2000/1100main.aspx
Pennsylvania November 2020 https://www.dos.pa.gov/VotingElections/OtherServicesEvents/VotingElectionStatistics/Documents/currentvotestats.xlsxNovember 2016 https://www.dos.pa.gov/VotingElections/OtherServicesEvents/VotingElectionStatistics/Documents/2016%20Election%20VR%20Stats.pdfNovember 2012 https://www.dos.pa.gov/VotingElections/Documents/Elections%20Division/Voter%20Registration%20Statistics/2012%20election%20GenElectionVoterRegisTotals.pdfNovember 2008 https://www.dos.pa.gov/VotingElections/Documents/Elections%20Division/Voter%20Registration%20Statistics/2008genelectionvoterregistotals.pdfNovember 2004 https://www.dos.pa.gov/VotingElections/Documents/Elections%20Division/Voter%20Registration%20Statistics/2004%20election%20nov.pdfNovember 2000 https://www.dos.pa.gov/VotingElections/Documents/Elections%20Division/Voter%20Registration%20Statistics/2000%20election%20nov.pdf
Wisconsin November 1, 2020 Voter Registration Statistics https://elections.wi.gov/node/7220November 2, 2016 Voter Registration Statistics https://elections.wi.gov/publications/statistics/registered-voters-2016-november-2November 5, 2012 Voter Registration Statistics https://elections.wi.gov/publications/statistics/registered-voters-2012-novOctober 2008 Voter Registration Statistics https://elections.wi.gov/publications/statistics/registered-voters-2008-october