What was the change in METRO AG headcount in 2019 from 2018?
{"METRO": {"2018": 92603, "2019": 89574}, "METRO Germany": {"2018": 13711, "2019": 13606}, "METRO Western Europe (excl.Germany)": {"2018": 27207, "2019": 27227}, "METRO Russia": {"2018": 13960, "2019": 12357}, "METRO Eastern Europe (excl.Russia)": {"2018": 29060, "2019": 28375}, "METRO Asia": {"2018": 8665, "2019": 8009}, "Others": {"2018": 7008, "2019": 7152}, "METROAG": {"2018": 909, "2019": 880}, "Total": {"2018": 100520, "2019": 97606}}
metroag_2019 = df["METROAG"]["2019"]
metroag_2018 = df["METROAG"]["2018"]
answer = metroag_2019 - metroag_2018