Table 2.

The eigenvalues and their contribution rates of the principal components

PCs	PC1	PC2	PC3	PC4	PC5	PC6	PC7	PC8	PC9	PC10	PC11	PC12	PC13	PC14	PC15	PC16
Eigenvalue	14.93	5.33	1.98	1.82	1.63	1.50	1.07	0.91	0.75	0.61	0.39	0.27	0.21	0.15	0.13	0.08
Contribution rate (%)	46.67	16.65	6.20	5.68	5.08	4.69	3.35	2.83	2.35	1.92	1.23	0.84	0.66	0.48	0.41	0.24