pre_text: Interest income (expense), net consisted of the following: Interest income is related to the cash and cash equivalents held by the Company. Interest expense recorded in 2019, 2018 and 2017 included respectively a charge of $39 million, $38 million and $37 million on the senior unsecured convertible bonds issued in July 2017 and July 2014, of which respectively $37 million, $36 million and $33 million was a non-cash interest expense resulting from the accretion of the discount on the liability component. Net interest includes also charges related to the banking fees and the sale of trade and other receivables. No borrowing cost was capitalized in 2019, 2018 and 2017. Interest income on government bonds and floating rate notes classified as available-for-sale marketable securities amounted to $6 million for the year ended December 31, 2019, $6 million for the year ended December 31, 2018 and $6 million for the year ended December 31, 2017.
table: Year ended December 31, 2019 Year ended December 31, 2018 Year ended December 31, 2017
table: Income 55 47 30
table: Expense (54) (54) (52)
table: Total 1 (7) (22)
question: Analyse this data from a financial earnings document. What is the increase/ (decrease) in income from December 31, 2018 to 2019?