condition mean min max ZT0-3 1978.0 1978.0 1978.0 ZT4-7 1908.0 1908.0 1908.0 ZT8-11 2168.6000000000004 2168.6000000000004 2168.6000000000004 ZT12-15 2763.3 2763.3 2763.3 ZT16-19 3076.65 3076.65 3076.65 ZT20-23 2560.5 2560.5 2560.5