  We present determinations of the total to selective extinction ratio R_V and
visual extinction A_V values for Milky Way stars using ultraviolet color
excesses. We extend the analysis of Gnacinski and Sikorski (1999) by using
non-equal weights derived from observational errors. We present a detailed
discussion of various statistical errors. In addition, we estimate the level of
systematic errors by considering different normalization of the extinction
curve adopted by Wegner (2002). Our catalog of 782 R_V and A_V values and their
errors is available in the electronic form on the World Wide Web.
