A simple solution would be to use linear regression to come up with a linear model of the database size.
Using this input generates the following output.
The equation of the slope of the line is what we're looking for: y = 4.107x + 8. We can use this to find when the database will reach its maximum size by determining where this function intersects with y = 50, the size of the database. This second equation is a horizontal line because the maximum size of the database does not vary with respect to x, time, which is the whole problem.
Looking for the intersection yields the following result:
Remember, however, that the answer, 10.2264, includes the days that have already gone by. We had seven days worth of input, so since our model predicts the database will fill up on day ten, we have roughly two days and some change. This is not a hard figure though, because remember that the database size is increasing irregularly and we could much more or much less time if our base data was not representative of the true database use, or if external factors that directly impacted database use changed.
Note that I did not include computations in the answer because I'm focusing on the high-level concept. I used the first linear regression calculator a quick google search pulled up and then plugged in the equation into Wolfram Alpha, so please actually do this yourself to verify the numbers are correct.
