What is the change in foreign exchange earnings from FY 2018 to FY 2019?
{"a. Foreign exchange earnings": {"FY 2019": 119499, "FY 2018": 92258}, "b. CIF Value of imports": {"FY 2019": 447, "FY 2018": 768}, "c.Expenditure in foreign currency": {"FY 2019": 49336, "FY 2018": 33014}}
a_foreign_exchange_earnings_fy_2019 = df["a. Foreign exchange earnings"]["FY 2019"]
a_foreign_exchange_earnings_fy_2018 = df["a. Foreign exchange earnings"]["FY 2018"]
answer = a_foreign_exchange_earnings_fy_2019 - a_foreign_exchange_earnings_fy_2018