What is ODS?

LibreOffice and OpenOffice's spreadsheet, and the ISO-standard one - the same ODF packaging an ODT uses, with sheets where a document has pages. Every cell stores its value and, separately, the text shown for it, which is why a figure formatted as currency can still be read back as the number underneath.

What is HTML?

The web's document format, and incidentally a place an enormous amount of tabular data ends up - published tables that were never offered as a download. Pulling those out is usually easier than asking whoever published them for the numbers.