What is the change in Wireless equipment revenue from 2018 to 2019?
{"Service ": {"2019": 65383.0, "2018": 64223.0, "2019 vs. 2018": 1160.0, "": 1.8}, "Wireless equipment ": {"2019": 18048.0, "2018": 18875.0, "2019 vs. 2018": -827.0, "": -4.4}, "Other ": {"2019": 7625.0, "2018": 6664.0, "2019 vs. 2018": 961.0, "": 14.4}, "Total Operating Revenues ": {"2019": 91056.0, "2018": 89762.0, "2019 vs. 2018": 1294.0, "": 1.4}, "Connections (000):(1)       -- Wireless retail connections ": {"2019": 94544.0, "2018": 94507.0, "2019 vs. 2018": 37, "": "\u2014"}, "Connections (000):(1)       -- Wireless retail postpaid connections ": {"2019": 90481.0, "2018": 89861.0, "2019 vs. 2018": 620.0, "": 0.7}, "Connections (000):(1)       -- Fios Internet connections ": {"2019": 5902.0, "2018": 5760.0, "2019 vs. 2018": 142.0, "": 2.5}, "Connections (000):(1)       -- Fios video connections ": {"2019": 4152.0, "2018": 4377.0, "2019 vs. 2018": -225.0, "": -5.1}, "Connections (000):(1)       -- Broadband connections ": {"2019": 6467.0, "2018": 6460.0, "2019 vs. 2018": 7.0, "": 0.1}, "Connections (000):(1)       -- Voice connections ": {"2019": 5754.0, "2018": 6332.0, "2019 vs. 2018": -578.0, "": -9.1}, "Net Additions in Period (000):(2)       -- Wireless retail ": {"2019": 379.0, "2018": 372.0, "2019 vs. 2018": 7.0, "": 1.9}, "Net Additions in Period (000):(2)       -- Wireless retail postpaid ": {"2019": 970.0, "2018": 1129.0, "2019 vs. 2018": -159.0, "": -14.1}, "Net Additions in Period (000):(2)       -- Wireless retail postpaid phones ": {"2019": 737.0, "2018": 498.0, "2019 vs. 2018": 239.0, "": 48.0}, "Churn Rate:      -- Wireless retail ": {"2019": 1.28, "2018": 1.25, "2019 vs. 2018": "", "": ""}, "Churn Rate:      -- Wireless retail postpaid ": {"2019": 1.05, "2018": 1.0, "2019 vs. 2018": "", "": ""}, "Churn Rate:      -- Wireless retail postpaid phones ": {"2019": 0.79, "2018": 0.76, "2019 vs. 2018": "", "": ""}, "Account Statistics:      -- Wireless retail postpaid ARPA ": {"2019": 118.13, "2018": 115.48, "2019 vs. 2018": 2.65, "": 2.3}, "Account Statistics:      -- Wireless retail postpaid accounts (000)(1)  ": {"2019": 33875.0, "2018": 34086.0, "2019 vs. 2018": -211.0, "": -0.6}, "Account Statistics:      -- Wireless retail postpaid connections per account(1)  ": {"2019": 2.67, "2018": 2.64, "2019 vs. 2018": 0.03, "": 1.1}}
wireless_equipment_2019 = df["Wireless equipment "]["2019"]
wireless_equipment_2018 = df["Wireless equipment "]["2018"]
answer = wireless_equipment_2019 - wireless_equipment_2018