If my students submit a report with statistics, it is expected that the numbers include a standard error of the mean (usually indicated by +/-). In your case, the arrival time is always accompanied by a +. This indicates that you are actually misrepresenting the true time at which the train arrives.
In the last few weeks*, my T,W,Th, Fri journeys have gone something like this:
25/10 14 mins late
26/10 24 mins late
27/10 on time (anomalous)
28/10 22 mins late (on hour earlier train)
1/11 8 mins late
8/11 10 mins late (am train)
9/11 30 mins late (this was on 17:22 start, which involved 2 delays and a sprint to have doors slammed in my face on connection)
10/11 29 minutes late
11/11 ~10 mins late (I'd stopped caring by end of week)
15/11 I forgot to look
16/11 trains *CANCELLED* after waiting for 2 hours at the station, Train Buddy drove us. (More on this in a forthcoming post).
17/11 10 mins late
18/11 morning train 11 late (and short 2 carriages), evening train 14 minutes and counting as I type.
*missing dates indicate days on which I was so fed up that I arranged to work from home.
Let's hope next week is better. Perhaps we might aim for 1-2 days of on-time service before December, when we can fully expect snow or leaves to shut the rails down altogether.
-Apologies to my dear readers for the complete lack of humor lately. I'm too annoyed and tired to even try to find the funny in this.