Based on the following principal component analysis, how many original variables are there in the dataset? Eigenvalues of Correlation Matrix Eigenvalue Difference Proportion Cumulative PC1 4.528 1.774 0.3019 0.3019 PC2 2.755 0.700 0.1837 0.4855 PC3 2.054 0.706 0.1370 0.6225 PC4 1.348 0.125 0.0899 0.7124 PC5 1.223 0.262 0.0815 0.7940 PC6 0.960 0.348 0.0640 0.8580 PC7 0.613 0.141 0.0408 0.8988 PC8 0.472 0.101 0.0315 0.9303 PC9 0.371 0.154 0.0247 0.9550 PC10 0.216 0.050 0.0144 0.9695 PC11 0.166 0.039 0.0111 0.9805 PC12 0.127 0.013 0.0085 0.9890 PC13 0.114 0.068 0.0076 0.9966 PC14 0.046 0.041 0.0031 0.9997 PC15 0.005 0.0003 1