Median by groups
 

My question is about median calculation. If there is a simple list of data,
its easy to do. But when we want to calculate median of a variable for one or
two groups then I dont know what to do ? Say I have a 300 line list
containing selling prices of a product in 30 shops for 10 years. I want to
see the median of the seeling price of this product for each year. When I
create a pivot table for this data, there are a number of averages (such as
arithmetic mean) which could be calculated by any group you want. But there
is not a solution for calculating median according to grouped data. If there
is a solution please let me know
Thank you in advance