main ingredient | 2013 | 2016 | 2019 | |||
Eigenvalues | Contribution rate/% | Eigenvalues | Contribution rate/% | Eigenvalues | Contribution rate/% | |
PC1 | 0.04177 | 88.12 | 0.025994 | 77.86 | 0.043087 | 80.47 |
PC2 | 0.003053 | 6.45 | 0.00457 | 13.69 | 0.007822 | 14.61 |
PC3 | 0.002123 | 4.47 | 0.002604 | 7.8 | 0.001695 | 3.17 |
PC4 | 0.000453 | 0.96 | 0.000218 | 0.65 | 0.000938 | 1.75 |