Mercury vapor's days (in my area anyway) are numbered.

http://www.greenvilleonline.com/story/news/local/2014/09/23/duke-energy-replace-sc-street-lights/16099353/

Most of the mercs here are still the clear ones. Only a few recent replacement lamps are DX coated. I'm hoping to use this as an opportunity to get some free Silverliners and other MV cobraheads.

I'm also surprised at the 25% remark. Between the town of 5000 and city of 34000 I live in, I haven't seen a single MV streetlight. The only surviving fixtures I've seen are on people's houses, so presumably not publicly owned.

I don't think 25% is a misprint. There really are a LOT of MVs here.

We just moved from a neighborhood served by Duke Progress.  It was an older subdivision built in the late 60s to early 80s.  Our end (the older part) still has small 175W mercury cobra heads.  The only HPS units (100W) are where a mercury fixture failed.  The one outside our house had a nice bright clear bulb, but some were phosphor coated.  The fixtures have a dull gray aluminum look (probably natural oxidation from 40+ years).  At least one was dayburning for years.  These seem to be pretty tough units.

I have seen Duke Progress put in LED street lights in the next town over.

Anyway, one data point from someone who normally doesn't post about street lights.

Matt

In my town, there is about a 5 mile stretch of highway that still has the original streetlights from when the highway was completed in the early 70's. They were all originally 175 watt MV, and most still are, but some have been converted to HPS. There is no word of modernizing them. The surviving fixtures all have that "dull grey look." There is even an article on Wikipedia about them. Read the second paragraph in "History."

On one major road in Anderson, there is a single GE Form 400 that is still operating with a clear MV lamp and can-shaped external ballast. A lot of the poles still have external ballasts abandoned in place, so it seems that the entire section of road had Form 400s at one time but only one was spared. I would love it if they kept the Form 400 installed despite the LED project, just for historical purposes. There is actually another Form 400 on the same road, but it's hidden between some buildings and doesn't light the actual roadway. Maybe that one will be spared too. There was a third Form 400 in town but it was recently replaced. I have Google Maps views of all three Form 400s in my "streetlights" album for those interested in seeing them.

Greenville, SC is unusual because almost all of its streetlights are mercury vapour. Some beautiful streetscapes up there at night. I will be sad to see them go. 

There are still quite a few mercs on Prince Edward Island

If anybody has ever been to Sterling, IL USA, its like a trip back in time (streetlight-wise) 90-95% of the municipal cobraheads are still 400w mercury. Theyre silver-grayish with a large/deep drop lens. Most are DX coated lamps, however about 10% are clear. Quite a few of them day burn and some are so dim, a 60w incandescent would be brighter. I don't know why this city never switched to HPS back in the late 80's-early 90's like everywhere else. In fact, Dixon, IL (just 10 min drive away) is all HPS like normal. I have relatives in Sterling, one cousin that works for the city, he says "these mercury cobraheads were installed in the 70's and some still have the original lamps in them" 40-year old mercury lamps still working (albeit very dim)

Essentially the same in Germany. It very much varies from town to town, between MV being almost extinct, with only a single-digit number of apparently forgotten fixtures left, and still being the most common lamp type (in some small towns at least two thirds of all street lights).

Lots of here too. Probably go past 30 yard blasters on the way to school. About half of the cobra heads along the roads are still . They are replacing them with as they fail.

I don't know why are regarded as bluish, some of the ones around here are very green. Some are more white.

I only have LED streetlights now in my area and they are very dull almost to the point of useless.

Probably energy saving is more important to your government than the quality of light and the reliability. LED in general lighting, can't last more than 12,000 hours max, while MV and old T12 fluorescents, proved that they could last 100,000 hours.

If you can rescue any of the ones they take down, I would LOVE to get a few!  I need to come visit you someday too!