The precision-indicating merging R factor value Rpim,
for merging all intensities in this data set.
Ref: Diederichs, K. & Karplus, P. A. (1997). Nature Struct.
Biol. 4, 269-275.
Weiss, M. S. & Hilgenfeld, R. (1997). J. Appl. Cryst.
30, 203-205.
Weiss, M. S. (2001). J. Appl. Cryst. 34, 130-135.