Table:
|  |  | Years Ended |  |  |  |
| --- | --- | --- | --- | --- | --- |
|  | July 27, 2019 | July 28, 2018 | July 29, 2017 | Variance in Dollars | Variance in Percent |
| Research and development | $ 6,577 | $ 6,332 | $6,059 | $245 | 4% |
| Percentage of revenue | 12.7% | 12.8% | 12.6% |  |  |
| Sales and marketing | 9,571 | 9,242 | 9,184 | 329 | 4% |
| Percentage of revenue | 18.4% | 18.7% | 19.1% |  |  |
| General and administrative | 1,827 | 2,144 | 1,993 | (317) | (15)% |
| Percentage of revenue | 3.5% | 4.3% | 4.2% |  |  |
| Total | $17,975 | $17,718 | $17,236 | $257 | 1% |
| Percentage of revenue | 34.6% | 35.9% | 35.9% |  |  |
Paragraphs:
Research and Development (“R&D”), Sales and Marketing, and General and Administrative (“G&A”) Expenses
R&D, sales and marketing, and G&A expenses are summarized in the following table (in millions, except percentages):
R&D Expenses R&D expenses increased due to higher headcount-related expenses and, to a lesser extent, higher acquisition-related costs, higher contracted services and higher discretionary spending.
We continue to invest in R&D in order to bring a broad range of products to market in a timely fashion. If we believe that we are unable to enter a particular market in a timely manner with internally developed products, we may purchase or license technology from other businesses, or we may partner with or acquire businesses as an alternative to internal R&D.
Sales and Marketing Expenses Sales and marketing expenses increased due to higher headcount-related expenses, higher discretionary spending and, to a lesser extent, higher contracted services and higher acquisition-related costs, partially offset by lower share-based compensation expense.
G&A Expenses G&A expenses decreased due to a benefit from the $400 million litigation settlement with Arista Networks and lower contracted services, partially offset by higher discretionary spending and higher headcount-related expenses.
Effect of Foreign Currency In fiscal 2019, foreign currency fluctuations, net of hedging, decreased the combined R&D, sales and marketing, and G&A expenses by approximately $233 million, or 1.3%, compared with fiscal 2018. In fiscal 2018, foreign currency fluctuations, net of hedging, increased the combined R&D, sales and marketing, and G&A expenses by approximately $93 million, or 0.5%, compared with fiscal 2017.
Question:
Which years does the table provide information for R&D, sales and marketing, and G&A expenses?