Table:
|  |  | Three Months Ended |  |
| --- | --- | --- | --- |
|  | December 31, 2019 | September 29, 2019 | December 31, 2018 |
|  |  | (Unaudited, in millions) |  |
| Net income attributable to parent company | $392 | $302 | $418 |
| As percentage of net revenues | 14.2% | 11.8% | 15.8% |
Paragraphs:
For the fourth quarter of 2019, we reported a net income of $392 million, compared to a net income of $302 million and $418 million in the prior and year-ago quarters, respectively. The fourth quarter 2019 net income represented diluted earnings per share of $0.43 compared to $0.34 in the prior quarter and $0.46 in the prior-year quarter.
Net income attributable to parent company
Question:
What is the average percentage of net revenues for the period December 31, 2019 and 2018?