[SR-Users] serctl moni command output question

We have old ser running and in "serctl moni" command output in "Transaction Statistics" section "waiting counter" is growing it's almost millions sometime i do restart to get it clear so wanted to understand what is that counter for and why its keep growing? see following output after restart its 237 but it will grow by time..

#serctl moni [cycle #: 20; if constant make sure server lives and fifo is on] Server: Vivox Proxy (0.10.99+cvs20050913 (i386/linux)) Now: Fri May 5 21:20:10 2017 Up Since: Sun Apr 30 02:31:34 2017 Up time: 499716 [sec]

Transaction Statistics Current: 73 (237 waiting) Total: 1015654 (0 local) Replied localy: 1748134 Deleted: 1015581 Completion status 6xx: 0, 5xx: 226, 4xx: 241347, 3xx: 0, 2xx: 848765