pre_text: Unaudited Pro Forma Information - OpenEye The following unaudited pro forma data is presented as if OpenEye were included in our historical consolidated statements of operations beginning January 1, 2018. These pro forma results do not necessarily represent what would have occurred if all the business combination had taken place on January 1, 2018, nor do they represent the results that may occur in the future. This pro forma financial information includes our historical financial statements and those of our OpenEye business combination with the following adjustments: (i) we adjusted the pro forma amounts for income taxes, (ii) we adjusted for amortization expense assuming the fair value adjustments to intangible assets had been applied beginning January 1, 2018, and (iii) we adjusted for transaction fees incurred and reclassified them to January 1, 2018. The pro forma adjustments were based on available information and upon assumptions that we believe are reasonable to reflect the impact of these acquisitions on our historical financial information on a supplemental pro forma basis, as follows (in thousands, except per share data):
table: Pro Forma
table: Year Ended December 31,
table: 2019 2018
table: Revenue $527,550 $451,013
table: Net income attributable to common stockholders 51,075 13,264
table: Net income attributable to common stockholders per share - basic $1.05 $0.27
table: Net income attributable to common stockholders per share - diluted $1.02 $0.26
question: Analyse this data from a financial earnings document. What was the change in the Net income attributable to common stockholders between 2018 and 2019?