Eccentricity vs. orbital period for the systems in our sample with orbit determination (blue open circles). The blue filled circle is the average value (e = 0.416 ± 0.043). The values for the additional objects from Table 7 are shown with plus signs. The grey squares and triangles are the average values for spectroscopic binaries obtained by Udry et al. (1998) and Griffin (2012), respectively. The grey diamonds are estimates of average values for long period visual binaries by Tokovinin & Kiyaeva (2016).