Table:
|  | Group |  |
| --- | --- | --- |
|  | 2019 | 2018 |
|  | S$ Mil | S$ Mil |
| Cost of equipment sold (1) | 3,106.1 | 2,696.7 |
| Other cost of sales | 2,767.1 | 2,499.2 |
| Staff costs | 2,597.3 | 2,760.1 |
| Selling and administrative costs (2) | 2,472.6 | 2,536.6 |
| Traffic expenses | 1,573.4 | 1,615.8 |
| Repair and maintenance | 388.0 | 367.9 |
|  | 12,904.5 | 12,476.3 |
Paragraphs:
5. Operating Expenses
Notes: (1) Includes equipment costs related to ICT services.
(2) Includes supplies and services, as well as rentals of properties and mobile base stations.
Question:
What is the average of the top 3 operating expenses subcategories in 2019?
Answer: (3106.1 + 2767.1 + 2597.3) / 3 = 2823.5