Just thought I would share this data point. I got my SDFCU Premium Cash Back + card about 3 years ago. The last two years on my February statement they have given me an auto-CLI.
Card was originally at $5k, then went to $8.5k, now it is at $12.5k.
I will admit the card got very little use this year, maybe a couple hundred a month if that. The increase doesn't seem to be tied to usage. I only opened one card last year, so relatively few new accounts and inquiries.
This card seems to grow naturally over time.
Congratulations on your SDFCU auto-CLI!