Body of the table

The following principles are recommended, illustrated in the table below.

Make sure that every table cell has information in it. For example, you could use na for not applicable or not available (define these in abbreviation notes under the table). Use 0 for a zero result only – do not use 0 for missing data. Some readers will also be used to seeing en dashes (–) for missing values. Consider whether this is appropriate for your particular readers. Also be aware that some assistive technologies may not be able to interpret en dashes.
Each data category or subcategory should have its own column or row.
Set column widths to comfortably accommodate their contents. Allow enough width for text cells to avoid long, narrow blocks of text. Standardise the amount of space between columns. Avoid stretching a table to fit the page width. For a series of similar tables, keep column widths consistent.
Copyedit and proofread tables so that they are consistent with the rest of the document. Check that totals and subtotals are correct.
Define any abbreviations or symbols used under the table.

Align all cell contents to the top of the cell, apart from column headings, which should be bottom-aligned.
Left-align the column heading and text in the left-hand column (the stub). Centre-align column headings for columns of numerical data, and left-align headings for columns of text data.
Left-align columns of text.

Use tabular lining or monospacing for all numbers – this is where each numeric character sits on the baseline, and occupies the same amount of horizontal and vertical space. This keeps numbers evenly spaced and vertically aligned.
Use the same style for spacing and punctuation within numbers as in the rest of the document. A comma in 4-digit numbers is preferred (eg 2,000, 10,000) so that large numbers align in the column.
Align all numbers in a column on the decimal point (even if the decimal point is not actually present) and round to the same number of significant figures or decimal places.
Centre columns of numbers under the headings – that is, make sure that the column of figures (which is aligned on the decimal point) has roughly equal amounts of space on the left and the right within the column.

In a text table, it is often unnecessary to use a full stop at the end of each entry, even if the entry is a full sentence.
Do not use more than 2 levels of text hierarchy.
Indicate explanatory table notes using superscript lower-case letters within the table, in alphabetical order from left to right and top to bottom. There is no need to put a space before the superscript letters, but ensure that they are clearly visible in the table. In large tables with a large amount of text, this may involve increasing the font size of the superscript and making it bold.

Table body cells

Australian manual of style