A quick examination of your workbook shows that many of the cells contain the character ascii code 160 (a non-breaking space, did you paste this data from the web? If you look at the source of the web page it would likely appear as  ) So I suggest one of two things:
1. Run a one line macro which will work on the entire active sheet:
Code:
Sub blah()
Cells.Replace What:=Chr(160), Replacement:="", LookAt:=xlPart, SearchFormat:=False, ReplaceFormat:=False
End Sub
or
2. follow the following instructions to the letter:
Select any cell with what looks like a number but you've found isn't a number. I've used H12 here:
and I've selected the whole value in the formula bar to show there are leading characters.
Select only one of those leading characters:
(they're quite narrow, use the arrow keys on the keyboard in conjunction with the shift key to be sure you only select one of them)
then on the keyboard put that single character into the clipboard with Ctrl+c on the keyboard.
Press the escape key.
Make sure you only have one (any) cell selected on the sheet (this means the whole sheet will be processed) or select a single range of cells that you want to limit the processing to.
Press Ctrl+h (this'll bring up the search and replace dialogue box).
In the Find what: field make sure it's empty first, then press Ctrl+v to paste that single character in there (you'll see nothing obvious in that field).
Then make sure the Replace with: field is empty.
The rest of the dialogue box should look like this:
Click on Replace All.
Dismiss the report message
Click Close.
That's it, you've finished.
The attached contains the macro. Click the button on the sheet to run it.