On 10Nov2023 0344, Charles McKnight - chuckmcknight at pheonic.com (via
tml list) wrote:
> Interesting. Is that from a particular version of Traveller so I can
> bone up on that?

There's a single mention in Classic's /Alien Module 5 - Droyne/,
p.34-35, though not as "D5", etc.

The first use of this format I've found is in the  late (1992)
MegaTraveller-era product /Astrogator's Guide to Diaspora/, and it's not
explained in the map keys, so I assume it was an established practice by
then.

TNE definitely uses this notation, and does explain it. The map keys in
/Path of Tears/ mentions that 'C:0', etc. mean 10 tenths of the
population is Chirper etc.

--
Rupert Boleyn <xxxxxx@gmail.com>