I suggest that you make a helper table, called Stats and enter one record into it. It will have record ID of 1.
Then build a relationship where one states has many detail records and let the system create a reference field called related stats. Edit the field properties for that field and make it a formula numeric with a value of 1.
Now you can add summary fields to that relationship, for example, to roll up a summary of the total consumption which was during the current month.
Then, if you need to know how many days have passed in the current month, you can make a field on the stats table with this formula.
Today() - FirstDayOfMonth(Today()) + 1