Stack Overflow
    --------------
    
    Questions  Accepted   >= 1 answers  Closed (Ex Deleted)
    10386638   5819260    9148900       443261

Here, 56% of questions have an accepted answer and 88% have 1 or more answer (i.e. 12% have no answers). 4% are closed.

<%%>

    Ask Ubuntu
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    Questions  Accepted   >= 1 answers  Closed (Ex Deleted)
    204114     69534      162546        27566

Here 34% of questions have an accepted answer and 80% have one or more answer (i.e. 20% have no answers). 14% are closed.

<%%>

    Unix and Linux
    --------------
    
    Questions  Accepted   >= 1 answers  Closed
    75899      38258      64049         4988

Here 50% of questions have an accepted answer and 84% have one or more answer (i.e. 16% have no answers). 7% are closed.