What comes after primary, secondary, tertiary apartment building investment markets?

What comes after primary, secondary, tertiary apartment building investment markets? I got to thinking about this after I read that MPF Research classifies a tertiary market as one with up to 100,000 units…. so I looked it up on the intertubes:
The sequence continues with quaternary, quinary, senary, septenary, octonary, nonary, denary. Words also exist for `twelfth order’ (duodenary) and `twentieth order’ (vigenary) according to www.answerbag.com