Table:
|  | 2019 | 2018 | 2017 |
| --- | --- | --- | --- |
| Stock-based compensation expense - Property | $1.8 | $2.4 | $2.1 |
| Stock-based compensation expense - Services | 1.0 | 0.9 | 0.8 |
| Stock-based compensation expense - SG&A | 108.6 | 134.2 | 105.6 |
| Total stock-based compensation expense | $111.4 | $137.5 | $108.5 |
| Stock-based compensation expense capitalized as property and equipment | $1.6 | $2.0 | $1.6 |
Paragraphs:
AMERICAN TOWER CORPORATION AND SUBSIDIARIES NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Tabular amounts in millions, unless otherwise disclosed)
14. STOCK-BASED COMPENSATION
Summary of Stock-Based Compensation Plans—The Company maintains equity incentive plans that provide for the grant of stock-based awards to its directors, officers and employees. The 2007 Equity Incentive Plan, as amended (the “2007 Plan”), provides for the grant of non-qualified and incentive stock options, as well as restricted stock units, restricted stock and other stock-based awards. Exercise prices for non-qualified and incentive stock options are not less than the fair value of the underlying common stock on the date of grant. Equity awards typically vest ratably, generally over four years for RSUs and stock options and three years for PSUs. Stock options generally expire 10 years from the date of grant. As of December 31, 2019, the Company had the ability to grant stock-based awards with respect to an aggregate of 7.0 million shares of common stock under the 2007 Plan. In addition, the Company maintains an employee stock purchase plan (the “ESPP”) pursuant to which eligible employees may purchase shares of the Company’s common stock on the last day of each bi-annual offering period at a 15% discount from the lower of the closing market value on the first or last day of such offering period. The offering periods run from June 1 through November 30 and from December 1 through May 31 of each year.
During the years ended December 31, 2019, 2018 and 2017, the Company recorded and capitalized the following stock-based compensation expenses:
Question:
What was the percentage change in Total stock-based compensation expense between 2018 and 2019?
Answer: ($111.4-$137.5)/$137.5 = -18.98