The National Conference of State Legislatures noted in this blog post that Washington chamber – eight times from 1982 to 2012 – is among the “most fickle” in the country, along with the Indiana and Montana house chambers, which also have had eight majority changes.
Among senates, Montana and Maine rank behind Washington with seven each, while Michigan and Minnesota switched six times.
Charts from the Washington Office of the Secretary of the Senate show the changes during the period.
The Senate chart is here. The House chart is here.
Updated to fix broken link.


