I have suggested this in the past. I was told that PSAudio stores up to 1 year of data. The data is deleted on January 1st and it starts over for the new year.
My suggestion is that it would be nice if they stored 1 year of data but on a rolling basis. This is so that on January 1st I could see data back to January 2nd. This came about when in the first week of January 2014 I went on to see the performance in December and found the data was no longer there.
Also I suggest that adding the ability to download the data over a user specified date range would be a nice feature. This would probably be downloaded into a .csv file.