pre_text: American Tower Corporation • 2019 Annual Report Appendix 1 • Letter to Stakeholders RETURN ON INVESTED CAPITAL (ROIC) RECONCILIATION1 ($ in millions. Totals may not add due to rounding.) 1 Historical denominator balances reflect purchase accounting adjustments 2 Represents Q4 2015 annualized numbers to account for full year impact of Verizon Transaction. 3 Represents Q4 2016 annualized numbers to account for full year impact of Viom Transaction 4 Adjusted to annualize impacts of acquisitions closed throughout the year. 5 Positively impacted by the Company's settlement with Tata in Q4 2018. 6 Excludes the impact of deferred tax adjustments related to valuation.
table: 2015 2 2016 3 2017 4 2018 4,5 2019 4
table: Adjusted EBITDA $3,206 $3,743 $4,149 $4,725 $4,917
table: Cash Taxes (107) (98) (137) (172) (168)
table: Maintenance Capex (124) (159) (115) (150) (160)
table: Corporate Capex (26) (27) (17) (9) (11)
table: Numerator $2,948 $3,459 $3,880 $4,394 $4,579
table: Gross PPE $14,397 $15,652 $16,950 $17,717 $19,326
table: Gross Intangibles 12,671 14,795 16,183 16,323 18,474
table: Gross Goodwill6 4,240 4,510 4,879 4,797 5,492
table: Denominator $31,308 $34,957 $38,012 $38,837 $43,292
table: ROIC 9.4% 9.9% 10.2% 11.3% 10.6%
question: Analyse this data from a financial earnings document. What was the change in adjusted EBITDA between 2016 and 2017?