I found a few mercs in communities like Etna, Millvale, O'hara, Robinson and West Deer Twp. Those areas have 99% HPS lights, it's nice to see a leftover mercury vapor light for once.
If areas had more mercury vapor streetlights, the skies would be less polluted at night.
If you use Google Maps and go to Amarillo, Texas, using the Street View you will notice that the city still has lots of mercs which include Form 400s. It must have about 80 to 90% of mercs in that city