The number of stellar systems within 10 parsecs (234 as of 1998.5) with various errors in the measured trigonometric parallaxes is shown. Parallaxes are used to measure distances to stars, and are measured in arcseconds. At a distance of 1 parsec (about 3.26 light years), a star would have a parallax of 1 arcsecond (or 1000 milliarcseconds), and at 10 parsecs, a parallax of 0.1 arcsecond (or 100 milliarcseconds). All of the systems in the 10 parsec sample have parallaxes of 100 milliarcseconds or larger. The systems represented by the green bins in the figure have errors less than 10 milliarcseconds, so their parallaxes (and distances) are known to better than 10%. The red bin represents systems with errors greater than 10 milliarcseconds, and these will require further work to deterimine more accurate parallaxes.