Not adding up

Now I am confused. I wrote recently about BBC World Service jobs, checking with publicly available annual reports, that "in 2009/10, there were 2,017 employees. In 2013/14 there were 1,583." 

But a new response to a Freedom of Information inquiry reports these figures, for World Service and Monitoring together. This says that the headcount on 31st of March for each year was 1209 (in 2013) 1169 (in 2014) and 1156 (in 2015).