If what we have in the registry is an accurate representation (thanks @fiatslug87!), 1988 MJs accounted for nearly 25% of MJ production (286/1166=.245 or 24.5%). 1986s account for approximately 25% of MJ production (293/1166=.251 or 25.1%). That said, we do not know if the registry actually shows the ratio or not. It looks like 88s and 86s are equally common though.