data
| Date | L，LF日 | L，LF晚 | L，LF夜 |
|---|---|---|---|
| dB | dB | dB | |
| 2021-Q4 | 37.6 | 36.3 | 31.8 |
| 2021-Q3 | 36.8 | 31.9 | 32.6 |
| 2021-Q2 | 37.0 | 31.3 | 30.3 |
| 2021-Q1 | 37.8 | 32.8 | 29.9 |
| 2020-Q4 | 37.8 | 33.1 | 31.2 |
| 2020-Q3 | 36.7 | 35.6 | 30.0 |
| 2020-Q2 | 37.0 | 33.0 | 29.6 |
| 2020-Q1 | 37.1 | 32.0 | 30.3 |
| 2019-Q4 | 36.6 | 31.7 | 28.6 |
| 2019-Q3 | 37.2 | 31.4 | 29.0 |
| 2019-Q2 | 37.8 | 32.9 | 30.1 |
| 2019-Q1 | 37.6 | 32.9 | 30.1 |
| 2018-Q4 | 38.0 | 34.9 | 30.5 |
| 2018-Q3 | 37.3 | 34.0 | 29.8 |
| 2018-Q2 | 37.5 | 33.1 | 31.5 |
| 2018-Q1 | 39.3 | 33.7 | 30.8 |
| 2017-Q4 | 38.4 | 33.1 | 31.9 |
| 2017-Q3 | 37.4 | 32.2 | 29.8 |
| 2017-Q2 | 38.6 | 36.2 | 32.5 |
| 2017-Q1 | 36.4 | 34.3 | 27.9 |
| 2016-Q4 | 38.6 | 36.8 | 34.2 |
| 2016-Q3 | 37.5 | 30 | 29.4 |
| 2016-Q2 | 35.3 | 32.4 | 28.2 |
| 2016-Q1 | 39.4 | 35.8 | 31.9 |
| 2015-Q4 | 41.2 | 35.6 | 34.9 |
| 2015-Q3 | 39.4 | 34.4 | 33.2 |
| 2015-Q2 | 44.2 | 37.9 | 37.4 |
| 2015-Q1 | 42.0 | 38.6 | 35.2 |
| 2014-Q4 | 52.3 | 45.4 | 44.6 |
| 2014-Q3 | 53.3 | 45.9 | 43.9 |
| 2014-Q2 | 53.0 | 46.1 | 45.0 |
| 2014-Q1 | 53.6 | 44.9 | 43.3 |
| 2013-Q4 | 41.7 | 39.2 | 34.6 |
| 2013-Q3 | 39.1 | 32.5 | 32.3 |
| 2013-Q2 | 41.4 | 38.0 | 33.7 |
| 2013-Q1 | 41.3 | 35.0 | 32.7 |