I think anyone at 40% or mor eloss is on the worst end of the trend.
Mine is also around that %.
110 when I first checked my stats, the lowest I seen whilst on fast path was low 60s. (not going to post interleaved figures as thats not like for like, thats artifical reduction by DLM). My line then got back to above 65 before syncing at 75 1am one morning about 9 or so weeks ago at a 4db margin, I am still on that sync now with 75mbit with a 3.9db snrm.
Its not necessairly about number of enabled lines but rather if a big disturber gets enabled. I had it seems 2 big disturbers enabled within a month of my service been installed and I was first on the cabinet, so arguably I was incredibly unlucky. Within a month of install down from 110 to 73. Since then any further drops in speed have been in small bites.
Of course I am also lucky that most of my loss of speed is above the 80 cap so not 40% loss of throughput.
Edited by Chrysalis (Sun 29-Jun-14 00:50:00)