Originally Posted by HighFlight

I'm sure you are correct. Many bypass upgrading for various reasons, some for a while, others for a long time. But the most junior numbers are usually what new hires are interested in, as it approximates more closely what they can expect if they come to work here.

And I'd like to correct the most junior hire dates; was looking at the list last night and assuming it was in seniority order. Of course, it wasn't. After looking again today in Excel, the most juniors are:

900 FO to 200 CA upgrade was a May 2015 hire
900 FO to 900 CA upgrade was a Jan 2011 hire
200 FO to 200 CA upgrade was a Feb 2011 hire
200 FO to 900 CA upgrade was a Sep 2010 hire

Not really a helpful metric (except that it shows that some opt not to upgrade), the most senior to upgrade on the last bid was a Aug 2006 hire.