Maybe showing the graphs will help. I uploaded a Word file with the graphs into a Google account so that I could share them. The axes got changed when I uploaded the graphs to Google, but the graphs are still correct.

Google: Document

For the price versus BV graph I used the high and low price for the quarter in order deliberately to add scatter.

I made one correction to the graphs. When I first posted I used data through Mar '25, but out of laziness I used the equation of the trendline through Dec '22. With the equation corrected the IV/BV is 1.32 as of Dec '99 and 1.53 as of Dec '24. The P/B in Q4 '99 ranged from 1.37 to 1.76, ending the quarter at 1.48. The P/B in Q4 '24 ranged from 1.47 to 1.63, ending the quarter at 1.51.

According to this analysis IV was below BV from 1965 to about 1980, but IV/BV is now about 1.54.

There have been three, distinct periods of BV growth and IV growth since 1965: 1965-1981, 1981-1999 and 1999 to present. The same is true of the S&P 500 index (not shown).

I hope this helps.