Comparison of different inflection points in hockey stick regression analyses
| Mean PbB | Hockey stick regression coefficient (SE) | R2 | AIC5-150 |
| 25 | 0.0114 (0.0046) | 0.1886 | 55.2946 |
| 28 | 0.0127 (0.0050) | 0.1893 | 55.2476 |
| 30 | 0.0139 (0.0054) | 0.1905 | 55.1672 |
| 31 | 0.0145 (0.0056) | 0.1908 | 55.1471 |
| 32 | 0.0151 (0.0058) | 0.1906 | 55.1569 |
| 33 | 0.0156 (0.0061) | 0.1901 | 55.1896 |
| 34 | 0.0162 (0.0063) | 0.1898 | 55.2153 |
| 35 | 0.0168 (0.0067) | 0.1892 | 55.2506 |
↵5-150 AIC=Akaike information criterion.