Here is how to put a main table adjacent to a separate row number table.
name
data
more data
cats
273
53
dogs
65
8,492
mice
1,649
548
1
2
3
The two tables are combined by wrapping them within a 3rd table that does not have a border. Look at the wikitext to understand. See examples below. It is not necessary to put text in the header cell above the number column. You can leave it blank, but sortable. Add <br> so it is not too narrow.
With wider tables the rows only line up between the table and the rank column if all the rows below the headers only use one line each. So it is a good idea to avoid tables that are too wide. For that reason avoid note columns, too. Narrow your browser window to see the problem with wider tables such as the one below. Another problem is that the rank column can drop down out of sight when the tables are viewed on a narrow screen, or when the browser width is narrowed.
Adding style="vertical-align:top;" will keep the tops aligned between the 2 tables at all browser widths. The rank column will not drop down.