We measure and analyze our segment performance on the basis of "adjusted operating revenue" and "adjusted operating income" or "adjusted operating loss", which differ from total revenue and income before income tax as presented in our consolidated statements of income due to the exclusion of net realized investment gains and losses and certain other items as specified in the reconciliations below. These performance measures are in accordance with GAAP guidance for segment reporting, but they should not be viewed as a substitute for total revenue, income before income tax, or net income.  A reconciliation of total revenue to "adjusted operating revenue" and income before income tax to "adjusted operating income" is as follows: Year Ended December 31 2019 2018 2017 (in millions of dollars) Total Revenue  $ 11,998.9  $ 11,598.5  $ 11,286.8  Excluding:  Net Realized Investment Gain (Loss) (23.2) (39.5) 40.3  Adjusted Operating Revenue  $ 12,022.1  $ 11,638.0  $ 11,246.5  Income Before Income Tax $ 1,382.1  $ 627.8  $ 1,404.0  Excluding: Net Realized Investment Gain (Loss) (23.2) (39.5) 40.3  Cost Related to Early Retirement of Debt (27.3) —  —  Long-term Care Reserve Increase —  (750.8) —  Loss from Guaranty Fund Assessment —  —  (20.6) Unclaimed Death Benefits Reserve Increase —  —  (39.0) Adjusted Operating Income $ 1,432.6  $ 1,418.1  $ 1,423.3  37