Record and Store Values From One Table to Another

Hi

I have been stuggling to find the right keywords to search online that would give me what I am looking for.

Here is my scenario. 

I have a table (we'll call SourceTable) that is comprised of one value. This provides the number of active customers and is connected via an SQL query that counts the volume of distinct customer numbers and returns as a single value.

This figure is fluid and changes daily when the SQL table refreshes but I would like to keep a record of the volumes each day for trend analysis purposes.

What I am asking for is help to build a HistoricData table that pulls data from SourceTable and appends them to the bottom of the HistoricData table with the date and customer volume for that day.

I'm sure this can be achived and I've no doubt the smart and wonderfull people on this forum would be able to provide a simple solution.

Any and all help is appreciated.

Kind regards

Paul