What should these comparisons return?

string s1 = "-0.67:-0.33:0.33";
string s2 = "0.67:-0.33:0.33";
string s3 = "-0.67:0.33:-0.33";
Console.WriteLine(s1.CompareTo(s2));
Console.WriteLine(s2.CompareTo(s3));
Console.WriteLine(s1.CompareTo(s3));