I am trying to develop a KPI for our Estimating Department in order to capture how many quotes are won and how many are lost. 

Tracking how many Requests for Quotation (RFQ) and Actual Quotes sent out is easy to track as by the end of the year the numbers should measure up, even if an RFQ was received in January but Quote sent out in Feb. 

The issue is tracking how many Quotes were converted into Sales for each financial year, as a Quote may be sent out March 2019 but not won/lost until eg. July 2020 causing it to be recorded in the following year's KPI register and hence not providing accurate and valuable information for reporting.  

My question is: What is the best way to capture how many quotes have been won/lost when the quote date and sales date may occur in different years?

Thank you