I am just posting to share some websites with great information about partisan balances in state legislatures.
First, if you can't figure out how to navigate through Ballotpedia, you might not come across this page: https://ballotpedia.org/Partisan_composition_of_state_legislatures
Next, there is a link on the Ballotpedia page to this site by the folks at the NCSL organization:http://www.ncsl.org/research/about-state-legislatures/partisan-composition.aspx
Finally, on the NCSL site, these three timelines are good historical information:
2002 - 2014 http://www.ncsl.org/documents/statevote/legiscontrol_2002_2014.pdf
1990 - 2000 http://www.ncsl.org/documents/statevote/legiscontrol_1990_2000.pdf
1978 - 1988 http://www.ncsl.org/documents/statevote/legiscontrol_1978_1988.pdf
Hard to envision that in Jan 1990 (so post Bush's 1988 election) the only Republican controlled states (both houses) were Arizona, Colorado, New Hampshire, South Dakota, Utah, and Wyoming. Democrats controlled 29 and 14 were split. I have a tough time grasping that, for instance, Idaho, Kansas, and North Dakota were not under GOP control. Things do change!