Incorrect checking for HTML5 <IFRAME> WIDTH as percent

I am trying with minimal success to add an iframe map to my new HTML5 webpage http://www.pearblossomhouse.com/pearblossom/documents/drainlake.html

Whilst trying to establish why my iframes do not display I got this checking error ...

Validation Output:
        
        1 Error
        
        


    
    
    
    Line 66,
        Column 111:
    Bad value 95% for attribute width on element iframe: Expected a digit but saw % instead.
    …me/N151.12061,6.11309,-3.06282,48.19144/Z8/" width="95%" height="200"></iframe>


This conflicts with the information on http://www.w3schools.com/html/html_iframe.asp where it says ...


Iframe - Set Height and Width
Use the height and width attributes to specify the 
size.

The attribute values are specified in pixels by default, but they can also be 
in percent (like "80%").


My knowledge may be incomplete as in - it is NOT permitted to do % from HTML5 - but it would be nice to know either way which is correct.


Meantime, I'm off to try to do it CSS ...



Thanks for your attention.


Harvey Partridge