MS Access Type Mismatch in Query to Count Instances of a String

Thank you for looking at my question,

I am trying to build a query that counts the number of occurrences of a string "On Time" in a query but it falls over with a type mismatch - why is that and please how do I fix it?

SELECT
qry2015_Receipts_to_Report_Detail.[BP Id],
qry2015_Receipts_to_Report_Detail.[BP Name],
qry2015_Receipts_to_Report_Detail.[Recd Year],
qry2015_Receipts_to_Report_Detail.[Recd Month],
Count(qry2015_Receipts_to_Report_Detail.[Delivery Perfomance]) AS [On Time]

FROM qry2015_Receipts_to_Report_Detail
GROUP BY qry2015_Receipts_to_Report_Detail.[BP Id], qry2015_Receipts_to_Report_Detail.[BP Name], qry2015_Receipts_to_Report_Detail.[Recd Year], qry2015_Receipts_to_Report_Detail.[Recd Month]

HAVING (((Count(qry2015_Receipts_to_Report_Detail.[Delivery Perfomance]))="On Time"));