When you set a decimal tab stop in a table, cell contents are automatically
aligned (without the need for a tab character) on (a) the decimal point, (b)
the place where the decimal point would be if there were one (i.e., the end
of the number), or (c) the first nonnumeric character other than the
thousands separator. That means that you can align numbers with and without
decimal places as well as numbers followed by footnote reference marks such
as * or a or by closing parentheses (for negative numbers).