NL yearly strikeout rate since 1954 with a runner on 3rd base and less than 2 outs compared to other cases

I used Stathead to get this data. In the table below the blue line shows the strikeout rate with a runner on 3rd base and less than 2 outs while the red line shows the strikeout rate in all other cases. Strikeout rate is SO/PA with IBBs and SHs taken out of PAs.

The two rates stayed pretty close to each other until around 1990. For some reason, the rate with a runner on 3rd and less than 2 outs has been lower than for other cases since then.

This next table shows the ratio of the runner on 3rd and less than 2 outs to the ration in other cases. As you can see, the ratio has been lower since around 1990.