When your goal is to have 100 items for this month and you only got say 80. What do you call the difference of 100 & 80, which is 20, in a company's term?
I really don't know may find it here http://www.bbc.co.uk/worldservice/learningenglish/business/
if ever you find it plz tell us we need to know
We failed to meet our monthly target by a 20% shortfall.