Fibre Speed Slowing Down Gradually

[#1]

I've been with PN for about 3 years now and during that time I've had very few drop outs and it's mostly been rock solid.  However, when I first joined I was getting about 76 Mbps down and 19 Mbps up.  Over the years though my download speeds have dropped to about 54 Mbps now on average.

I've done the checker and it states my line max speed is now 62 Mbps.  Has my line degraded over the years?  Just seems strange that for such a long time I was getting almost top speed and now it's dropped almost 20 Mbps. 

I still love my speeds but it would be nice to know if anything's wrong with my line or profile.

This is a link to a post of mine ref speeds last year, it has the line test which shows my IP Profile at 77 Mbps:

https://community.plus.net/t5/Fibre-Broadband/Speed-Drop/m-p/1215745

Also added my last BT test that shows IP Profile now at 62 Mbps.

Cheers.

[#2]

Just been on chat and basically been told it's down to too many connections in my area.

[#3]

I would assume that they are referring to the "crosstalk" effect http://www.kitz.co.uk/adsl/btwchecker.htm

[#4]

This is probably the crosstalk effect ww.kitz.co.uk/adsl/btwchecker.htm

As of 2014 more lines seem to be showing the effects of crosstalk as more users are added to the FTTC cabinet.  Although BT started using the term 'impacted' in 2013, it wasn't until cross-talk actually reached the stage of possibly impacting on my connection speed (rather than max headline) that the 'impact' figures appeared in my results.  15Mbps seems to be a fair average for most lines.  Over a 6 month period I have lost 20Mbps from my own max headline speed due to cross talk.