# UT-date ZP measured mean ZP measured stddev 20090515 22.8072 0.1129 20100224 22.9103 0.2685 20100225 22.8062 0.0735 20100501 22.6610 0.0000 20100504 22.7380 0.0224 20100505 22.8487 0.0167 20100615 23.3675 0.0928 20100618 23.0940 0.0410 20100711 23.1230 0.0886 20100714 23.1773 0.0669 20100715 23.1998 0.0462 20100923 22.6265 0.0575 20101102 21.1670 0.0000 20110211 22.8740 0.0279 20110418 23.0297 0.0274 20120502 23.7344 0.0182 20120516 23.0403 0.0198 20120620 22.7327 0.0366 20120623 22.8590 0.0194 20120803 22.8932 0.0351 20140902 22.9988 0.0438 20140904 23.0195 0.0503 20141005 22.5911 0.0890 20141006 22.8070 0.0373 20141105 22.9517 0.0578 20141128 22.9677 0.0392 20141209 22.9852 0.0401