Table:
|  |  | Years ended December 31, |  |
| --- | --- | --- | --- |
|  | 2018 | 2019 |  |
|  | NT$ | NT$ | US$ |
|  |  | (in thousands) |  |
| Audit Fees (1) | 52,794 | 62,040 | 2,074 |
| Audit-related Fees (2) | 1,283 | 1,095 | 37 |
| Tax Fees (3) | 4,304 | 3,943 | 132 |
| Total | 58,381 | 67,078 | 2,243 |
Paragraphs:
The following table sets forth the aggregate fees by categories specified below in connection with certain professional services rendered by Ernst & Young, our principal external auditors, for the years indicated.
(1) Audit fees consist of fees associated with the annual audit, review of our quarterly financial statements, statutory audits and internal control review. They also include fees billed for those services that are normally provided by the independent accountants in connection with statutory and regulatory filings.
(2) Audit-related fees consist of fees billed for assurance and services related to the performance of the audit or review of our financial statements but not described in footnote (1) above. These services include certification of our Singapore Branch to Singapore authorities and application for corporation registration.
(3) Tax fees include fees billed for professional services rendered by Ernst & Young, primarily in connection with our tax compliance activities.
All audit and non-audit services performed by Ernst & Young were pre-approved by our audit committee. In certain circumstances, the audit committee delegates to one designated member to pre-approve such audit and non-audit services. Pre-approval by a designated member should be reported to the audit committee at its upcoming meeting.
Question:
What constitutes Audit fee?