Currently it is not possible to see trends using a monthly chart because:
1. There's too much variability.
2. The number of days per month isn't constant.
Waiting for a year to elapse is too long. Therefore, can there be also quarterly charts in Simutrans i.e. charts showing data points for
Q1: Jan-Mar Q2: Apr-Jun Q3: Jul-Sep Q4: Oct-Dec
?
I think it's possible to see quarterly performance year-over-year (https://www.investopedia.com/terms/y/year-over-year.asp) (e.g. Q1 performance this year compared to Q1 performance last year) just by eyeballing such a chart.
The months have exactly the same length, the length of the days are different. Time is just display, and has little relation with "real" time. You can even play Simutrans with three days per months setting.
You could also play with shorter month. At twice shortening, the yearly statistics become quarterly ones ...
Thanks for the reply! The bits_per_month setting doesn't seem to provide the kind of control that I want so I suppose the answer is somewhere in the source code.
Or maybe dropping bits_per_month by 2 does do what I want, but I also do want to keep the yearly statistics as they are now.