What is the percentage change in revenue between 2018 and 2019?
{"Cloud and related solutions": {"2019": 896164, "2018": 766377}, "Software and services": {"2019": 52364, "2018": 58101}, "Maintenance": {"2019": 48282, "2018": 50581}, "Total revenues": {"2019": 996810, "2018": 875059}}
total_revenues_2019 = df["Total revenues"]["2019"]
total_revenues_2018 = df["Total revenues"]["2018"]
answer = ( total_revenues_2019 - total_revenues_2018 ) / total_revenues_2018 * 100.0