BUG: fix percentiles being dropped in Description frame.
BUG: fix percentiles being dropped in Description frame.

bashtage/statsmodels,bashtage/statsmodels,statsmodels/statsmodels,statsmodels/statsmodels,josef-pkt/statsmodels,statsmodels/statsmodels,bashtage/statsmodels,josef-pkt/statsmodels,josef-pkt/statsmodels,bashtage/statsmodels,statsmodels/statsmodels,josef-pkt/statsmodels,bashtage/statsmodels,josef-pkt/statsmodels,statsmodels/statsmodels,bashtage/statsmodels,statsmodels/statsmodels,josef-pkt/statsmodels