>                    -------------arrivals in-----------
>                     last     last     last       last
>                    1 day    2 days   3 days     7 days
>                    ------   ------   ------     ------
>  196 groups (all groups sampled.)
>        Expected:    33538    35087    36056      31338
>          Actual:    22762    n/a      23733        n/a
>         Percent:      68%    n/a        66%        n/a
> 
> What does n/a mean?