Widget product list - number of sales

I want to show with a widget my top 10 of sales. No problem would you think. There is the widget product list and you can order by the number of sales.
But...I don't know where that widget collect the data, for sure it is far away from reality.

It's showing the products that I have sold 9 or 8 times. Products what I sold 74! times are not in the list...
What to do?