What percentage of total government revenue was from product sales in 2019?
{" Restaurant/Retail --    Core": {"2019": 78238, "2018": 102877}, " Restaurant/Retail -- Brink *": {"2019": 41689, "2018": 25189}, " Restaurant/Retail -- SureCheck": {"2019": 3380, "2018": 6003}, " Restaurant/Retail --  Total Restaurant Retail": {"2019": 123307, "2018": 134069}, " Government --    Intelligence, surveillance, and reconnaissance": {"2019": 29541, "2018": 30888}, " Government -- Mission Systems": {"2019": 33513, "2018": 35082}, " Government -- Product Sales": {"2019": 871, "2018": 1207}, " Government --  Total Government": {"2019": 63925, "2018": 67177}}
product_sales_2019 = df[" Government -- Product Sales"]["2019"]
total_government_2019 = df[" Government --  Total Government"]["2019"]
answer = product_sales_2019 / total_government_2019 * 100.0