I can only speak of my experience. I got my Discover in 10/2003 and up to last year I averaged a CLI about once a year for $1,000-$1,200 just like clockwork. But it suddenly stopped and I don't know why.
I charged right at $30,000 in 2010 but I also haven't paid them any interest in over a year. 
But that's ok. If that's the reason for no recent CLI then I won't be getting any in the future either.
From a BK years ago to:
EX - 9/09 pulled by lender 802, EQ - 2/11-816, TU - 2/11-782
"Some people spend an entire lifetime wondering if they've made a difference. The Marines don't have that problem".
My auto CLI with Discover More came after 6 months and it took me from $2500 to $3000.
