Table 3. Summary of the PCA-analysis of the original descriptors, describing the eigenvalues of the covariance matrix, the total variance explained (cumulative R²) and the predictive ability (cumulative Q²).

Principal Component	Eigenvalue	Cumulative R2	Cumulative Q2
1	86.9	0.467	0.448
2	29.5	0.626	0.602
3	12.1	0.691	0.639
4	11.6	0.753	0.701
5	5.74	0.784	0.720
6	5.16	0.812	0.743
7	4.42	0.836	0.764
8	3.53	0.854	0.781
9	2.58	0.868	0.789
10	2.17	0.880	0.797
11	1.94	0.890	0.807