Good Afternoon

Please could someone help....

I have a monster spreadsheet that tracks recruitment numbers and as part of
our monthly reporting i need to count various monthly stats

The information i need to summarise for each department is:

the number of internal candidates that were offered in each month
The number of external candidates that were offered in each month
the number of internal candidates that started in each month
The number of external candidates that started in each month,

Sample Data as follows:
Department Candiate type offer date Start date
Engineering Int 01/01/2010 01/02/2010
Supply Chain Int 31/12/2009 01/03/2010
Engineering Ext 01/01/2010 23/02/2010
Supply Chain Ext 15/01/2010 01/03/2010
Projects Ext 17/03/2010 01/04/2010
Projects Ext 01/02/2010 01/03/2010

Any suggestions greatefully received.

Many thanks