extremely significantP < 0.01
The results were classified into five categories: extremely significant increase ( SLOPE > 0, P < 0.01), significant increase ( SLOPE > 0, 0.01 < P < 0.05), extremely significant decrease ( SLOPE < 0, P < 0.01), significant decrease ( SLOPE < 0, 0.01 < P < 0.05), and insignificant change ( P > 0.05).