Table 5 Correlation analysis.
Variable | 2000 | Significance | 2005 | Significance | 2010 | Significance | 2015 | Significance | 2020 | Significance |
|---|---|---|---|---|---|---|---|---|---|---|
E | 0.2181*** | 0.04312 | 0.3466 | 0.02466 | 0.144** | 0.04116 | 0.875*** | 0.044355 | 0.000729** | 0.000921 |
I | 0.115 | 0.01243 | 0.2822 | 0.04578 | 0.2941** | 0.01202 | 0.89 | 0.033745 | 0.000744* | 0.000734 |
U | − 0.1085 | 0.04304 | 0.4429*** | 0.02366 | 0.1838 | 0.04947 | 3.6875 | 0.030473 | 0.003073 | 0.000432 |
T | 0.132*** | 0.01367 | 0.4739 | 0.01514 | 0.1224 | 0.01131 | 3.93*** | 0.029591 | 0.00327** | 0.001006 |
TA | 0.1843** | 0.0343 | 0.4839** | 0.046 | 0.2907*** | 0.01904 | 2.7375 | 0.0438*** | 0.002281 | 0.001125 |
O | 0.3843 | 0.0426 | 0.1519 | 0.04158 | 0.1709 | 0.02948 | 1.347 | 0.020891 | 0.001122 | 0.304059 |
ER | 0.2146* | 0.01552 | 0.1783* | 0.03674 | 0.3071** | 0.03994 | 1.68** | 0.037745 | 0.0014 | 0.358119 |
ES | − 0.3619 | 0.01596 | 0.344 | 0.01495 | 0.1718 | 0.01663 | 3.214 | 0.035564 | 0.002678 | 0.435545 |
TR | 0.2123 | 0.02787 | 0.4785 | 0.03424 | 0.3072 | 0.02397 | 1.3975 | 0.028882 | 0.001165 | 0.168911 |
H | 0.03 | 2.798 | 0.602** | 1.613 | 0.38** | 2.956 | 0.439** | 0.106 | 0.133*** | 0.1379 |
D | − 0.1023* | 0.0293 | − 0.1704* | 0.04701 | − 0.3236** | 0.04915 | − 2.2375* | 0.043791 | − 0.00186** | 0.196733 |
W | 0.3487 | 0.01573 | 0.271 | 0.01024 | 0.3379 | 0.03609 | 3.343 | 0.035645 | 0.002786 | 0.167525 |