The phrase "decline rates" refers to the percentage or proportion of something that is decreasing or going down over a certain period of time. Full definition
By using a comprehensive database of the giant oil field production, the average decline rates of the world's giant oil fields are estimated. (peakoil.net)
He explained to me that the agency's new projections were based on a major study it had undertaken into decline rates in the world's 800 largest oil fields. (monbiot.com)
This is despite their being more cautious, with bank average decline rates up 2.8 % year on year. (reimag.co.za)