How reliable are the EWR-DCA evening flights in the Summer months?

I know there are trains to DC, and shuttle flights out of LGA, but I have specific needs to fly the early evening flights out of EWR to DCA. Train and Shuttle flights are totally not options to consider.

Just want to find out from those who fly frequently from EWR to DCA on UX to see how reliable these flights are in terms of on-time and cancellation trend.

Thanks