Table:
| (In millions, except percentages and per share amounts) | 2019 | 2018 | 2017 | Percentage Change 2019 Versus 2018 | Percentage Change 2018 Versus 2017 |
| --- | --- | --- | --- | --- | --- |
| Operating income | $42,959 | $35,058 | $  29,025 | 23% | 21% |
| Net tax impact of transfer of intangible properties | 0 | 0 | 0 | * | * |
| Net impact of the TCJA | 0 | 0 | 0 | * | * |
| Restructuring expenses | 0 | 0 | 306 | * | * |
| Non-GAAP operating income | $42,959 | $35,058 | $ 29,331 | 23% | 20% |
| Net income | $39,240 | $16,571 | $ 25,489 | 137% | (35)% |
| Net tax impact of transfer of intangible properties | (2,567) | 0 | 0 | * | * |
| Net tax impact of the TCJA | 157 | 13,696 | 0 |  |  |
| Restructuring expenses | 0 | 0 | 243 | * | * |
| Non-GAAP net income | $36,830 | $30,267 | $ 25,732 | 22% | 18% |
| Diluted earnings per share | $5.06 | $2.13 | $ 3.25 | 138% | (34)% |
| Net tax impact of transfer of intangible properties | (0.33) | 0 | 0 | * | * |
| Net tax impact of the TCJA | 0.02 | 1.75 | 0 | * | * |
| Restructuring expenses | 0 | 0 | 0.04 | * | * |
| Non-GAAP diluted earnings per share | $4.75 | $3.88 | $ 3.29 | 22% | 18% |
| * not meaningful |  |  |  |  |  |
Paragraphs:
NON-GAAP FINANCIAL MEASURES
Non-GAAP operating income, net income, and diluted EPS are non-GAAP financial measures which exclude the net tax impact of transfer of intangible properties, the net tax impact of the TCJA, and restructuring expenses. We believe these non-GAAP measures aid investors by providing additional insight into our operational performance and help clarify trends affecting our business. For comparability of reporting, management considers non-GAAP measures in conjunction with GAAP financial results in evaluating business performance. These non-GAAP financial measures presented should not be considered a substitute for, or superior to, the measures of financial performance prepared in accordance with GAAP.
The following table reconciles our financial results reported in accordance with GAAP to non-GAAP financial results:
* Not meaningful.
Question:
How do these non-GAAP measures aid investors?
Answer: We believe these non-GAAP measures aid investors by providing additional insight into our operational performance and help clarify trends affecting our business.