raw data from: NY Times COVID github page (snapshot on April 15, 2020)
Each data point is the doubling time derived from a best exponential fit of the trailing 7 days of reported case numbers.
Thumbnail graphs of doubling time for each state follow. States without enough data for the analysis are omitted. Where states have implemented a lockdown order, the pre-lockdown period is shaded in green, red thereafter. States are sorted by number of cases as of April 15, 2020.
Doubling time is improving (increasing) in nearly every state lately. WA is approaching a doubling time of 40 days, ID recently exceeded that figure.