I think the data listed does not add up, particularly the percentages for households with single parents and for households for married couple parents.
I went to this website and got the state by state data for total households by state:
https://worldpopulationreview.com/state-rankings/households-by-state
Then I took the percentages shown in the report and applied them to the total households.
The results for the percentages for the category single parent households do not agree with the sum of the numbers from the columns identified as “single female head of household no partner” plus “single male head of household no partner”. The numbers have under reported what the percentages suggest.
I would surmise the definition of households is the issue.