Hi,
Dealing with the same issue and here to express my support.
Hubspot declares itself to be a Sales Software, trying to make our lifes easier, but actually struggles with calculating conversion rates? 
Seems odd to me (and apparently many other, too).
Setting the filter to “any” is not the ideal solution, since it only shows the number of deals, not the conversion in percentage.
This is a feature we urgently need.
Pls fix.