If you want to do the same with your data, go here, stick your username in the box and wait for everything to be collected. You have to do this if you want your data updated too.
Some people seem to have a few corrupted weeks, for example this should be one for lbf but an artist has become '??t?Ê?¤?Õ'. Not sure what I can do about that. If you get any errors, report them back here or PM me and I'll see if they can be fixed. (It'll tell you of an error the first time you make a chart but if you're loading one that's been cached then you won't get the notice.)
The rest is self-explanatory. Oh, dates must be in the format dd-mm-yyyy. And numitems is the number of artists to display in the chart.