The statistics below is mainly from here and updated by my own research on the old forums.
@Teinyhr: CCP Abraxas’ first chronicle was from 2006 - this one where he also gets introduced as a new chronicle author. The early chronicles (from EVE beta phase or even before up to around March 2005) are all in the question mark category below. I never found an indication who wrote them.
Chronicles|Author
=================
97 CCP Abraxas
89 ?
10 CCP Gnauton
7 CCP Delegate Zero
5 CCP Greyscale
4 CCP Dropbear
3 CCP Ginger
3 CCP Headfirst
3 Community
2 CCP Big Dumb Object
2 CCP Jasonitas
1 CCP Abraxas, Tony Gonzales
1 CCP Eterne
1 CCP Falcon
1 CCP Molock
1 CCP t0rfifrans
1 CCP Technobabble
1 ISD Archetys Traum, ISD Sheliak Mesarthim, ISD Starsweaver,
ISD Mercury Team, Team Murder Services
1 NTRabbit
1 Orestes
===
234
For 3 chronicles I found a hint somewhere that they have been written by the “Community”. I believe, NTRabbit and Orestes were/are players as well, but I’m not sure. The very recent chronicle “Mithra’s Gate” has a question mark.