Piwik stats vs disk usage

I have a question about Piwik stats program:

I have piwik program in my website.
example: If my website has 10 visitors in 15 August and I have disk
space usage 49.24mb/10GB
If my website has 15 visitors next day in 16 August the disk usage
change or stay stabled?
THE QUESTION: As add statistics day by day the disk space change or not?

Please reply.

When you have a .txt with 10 words and you increase it to 100 words, the space the .txt consumes increases as well.
(example given, as it is easy to counter-check for better understanding)

Statistics stored by Piwik take up space in your database, thus the size of the database increases and takes up more disk space.
On the other hand: the Piwik installation itself stays unchanged in size.

So long,