Anyone have any insight into this:
https://www.ngccoin.com/price-guide/world/peru-1-2-sol-km-247-1966-1973-cuid-1095065-duid-1546697
All of the years of this type are worth 10 to 20 cents except for 1968, which has a book value of $12 in XF. The mintage is no lower than any of the other years. The only thing I could think of is that the JAS mintmarked version is the common one, and the one with no mintmark is very scarce in proportion. Other than that it doesn't seem to make sense. Does anyone know the reason? Or is it just an error in Krause?