What percentage of total balance consists of ACI on Demand in 2019?
{"Gross Balance, prior to December 31, 2018": {"ACI On Demand": 183783, "ACI On Premise": 773340, "Total": 957123}, "Total impairment prior to December 31, 2018": {"ACI On Demand": "\u2014", "ACI On Premise": -47432, "Total": -47432}, "Balance, December 31, 2018": {"ACI On Demand": 183783, "ACI On Premise": 725908, "Total": 909691}, "Goodwill from acquisitions (1)": {"ACI On Demand": 370834, "ACI On Premise": "\u2014", "Total": 370834}, "Balance, December 31, 2019": {"ACI On Demand": 554617, "ACI On Premise": 725908, "Total": 1280525}}
balance_2019 = df["Balance, December 31, 2019"]
aci_on_demand = balance_2019["ACI On Demand"]
total_balance = balance_2019["Total"]
answer = aci_on_demand / total_balance * 100.0