Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Age (ethnicity) | n | V1 | V2 | V3 | V4 | V5 | V6 |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1 week - 1 y | 210 | 92% | 74% | 27% | 20% | 0.5% | 0% |
| 1 y - 2 y | 154 | 96% | 85% | 39% | 10% | 0.7% | 0% |
| 2 y - 5 y | 202 | 98% | 50% | 22% | 7% | 1% | 0% |
| 5 y - 8 y | 94 | 91% | 25% | 14% | 5% | 1% | 1% |
| 8 y - 16 y | 90 | 62% | 7% | 2% | 0% | 0% | 0% |
| Males |  |  |  |  |  |  |  |
| 12 y - 13 y | 209 | 47% | 7% | 0% | 0% | 0% | 0% |
| 13 y - 14 y | 260 | 35% | 4.6% | 0.8% | 0% | 0% | 0% |
| 16 y - 19 y (whites) | 50 | 32% | 0% | 0% | 0% | 0% | 0% |
| 16 y - 19 y (blacks) | 310 | 46% | 7% | 2.9% | 1.3% | 0% | 0% |
| 20 - 30 y (whites) | 285 | 41% | 0% | 0% | 0% | 0% | 0% |
| 20 - 30 y (blacks) | 295 | 37% | 0% | 0% | 0% | 0% | 0% |
| Females |  |  |  |  |  |  |  |
| 12 y - 13 y | 174 | 69% | 11% | 1.2% | 0% | 0% | 0% |
| 13 y - 14 y | 154 | 52% | 8.4% | 1.4% | 0% | 0% | 0% |
| 16 y - 19 y (whites) | 50 | 66% | 0% | 0% | 0% | 0% | 0% |
| 16 - 19 y (blacks) | 310 | 73% | 9% | 1.3% | 0.6% | 0% | 0% |
| 20 - 30 y (whites) | 280 | 55% | 0% | 0% | 0% | 0% | 0% |
| 20 - 30 y (blacks) | 330 | 55% | 2.4% | 1% | 0% | 0% | 0% |
Question:
what is the first age in which t waves are measured?
Answer:
1 week