As sz4kerto said, it was probably tracked by building systems. But beyond that, weather services track every single lightning strike in most of the developed world. Eg BELLS: http://radar.meteo.be/en/3337408-Lightning+detection.html#pp...

This is how, for example, you can know whether a wildfire was started by lightning - once a point of origin is determined, simply check the data for strikes.

https://en.wikipedia.org/wiki/Lightning_detection http://www.lightningmaps.org/

Yes, lots of folks are counting.

http://www.blitzortung.org/

Building power management systems can detect this.

Could also be security cameras in addition to what others mentioned.