I would like to determine a percentage in Excel that is based on
multiple conditions.  This is for a serious a products on different
displays and the quantity on those displays.  I need to know out of
all the stores surveyed, what percentage of those stores had a lobby
display with more than 150 cases. If I had a small set of data I'm
sure I could just pivot the data a few ways and be done, but I have
over 50,000 rows.  See the sample set of data below for more detail.

Store    Display        Product        Qty
-------    --------------    --------------    ----------
123    Lobby        Soda Cans    50
123    Aisle        Soda Cans    75
123    Perimeter    Soda Cans    75
123    Lobby        2 liter        120
123    Aisle        2 liter        200
123    Perimeter    2 liter        50
123    Lobby        20 oz        20
123    Aisle        20 oz        60
123    Perimeter    20 oz        0
456    Lobby        Soda Cans    100
456    Aisle        Soda Cans    50
456    Perimeter    Soda Cans    50
456    Lobby        2 liter        25
456    Aisle        2 liter        150
456    Perimeter    2 liter        25
456    Lobby        20 oz        20
456    Aisle        20 oz        60
456    Perimeter    20 oz        0
789    Lobby        Soda Cans    40
789    Aisle        Soda Cans    100
789    Perimeter    Soda Cans    20
789    Lobby        2 liter        80
789    Aisle        2 liter        200
789    Perimeter    2 liter        50
789    Lobby        20 oz        40
789    Aisle        20 oz        60
789    Perimeter    20 oz        0

only 2 of them (66%) have a Lobby display with more than 150 cases. In
Excel 2003, how I can I do this? I cannot wrap my head around it.
Thank you in advance for your assistance.