What does the tick mean?

[rubymelia]

Unsure what the ticks mean in this 1901 census? It's in the column for 1. Deaf and dumb 2. Blind 3. Lunatic 4. Feeble minded
Father and mother of my g-grandmother have a tick each in this column. 
There's no number accompanying the tick. 

[KGarrad]

I think it's just an enumerator's mark, showing the non-English people?

I've seen it quite a few times before.

[stanmapstone]

You can see an actual example of the 1901 at http://www.rootschat.com/links/02fc/ where the clerk in the census office has put ticks and other marks as he has extracted the details for the census report.
He has put red marks opposite people from foreign countries.
Stan

[stanmapstone]

The marks on the page are made by the census clerk extracting occupations etc., On the pages of the original books these marks are in coloured inks, crayon, or pencil, and can be easily differentiated from the enumerators' returns but not on the monochrome images.

Stan