One thing that can make them explode because the utility typically run them ‘hot’, putting say 180kva of load on a 150kva transformer. The transformer can deal with the increased load at the expense of being hotter, the cost is shorter lifespan for the pole mounted transformers.
Pole mounted utility transformers are built to handle weather.
With higher voltages, fewer transformers are needed. Power lines are buried, and transformers are generally larger and not exposed to weather.
I am not criticizing the infrastructure but as European (and this is something others told me) it feels weird to see transformers hanging from poles and every now and then blowing up.
And I mentioned the weather because my experience is that it usually happens during storms, it might be lightnings or tree branches but that is what I have seen.
At first I couldn't find equivalent European statistics, until I changed my search to "minutes", which is how Europe measures outages. The EU average in 2010-2014 was just over 2 hours, and as low as 29 minutes in Germany, or 20 here in Denmark.
[1] https://www.eia.gov/todayinenergy/detail.php?id=54639
[2] https://neon.energy/Neon_Data-quality_European-Commission.pd... (22nd page, figure 5)
Most power outages are broken wires. According to my utility underground wires break more often than above ground, and when they break are a lot more expensive to fix. (They are trying to make a point so this might need some salt, though i don't care enough to look up what)
Buried power lines solve most of these.
You won't find the statistic you want for Europe, as transformers don't explode enough for them to listed separately to any other fault.
I am from Spain and living in the US and something that was shocking to me about it is that here, at least where I lived, these last transformers are hanging from poles and every now and then I can hear an explosion and it is one of them blowing up.
I have no idea but, maybe being exposed like they are here in the US makes them more vulnerable to weather conditions and that makes them explode? Or maybe it simply is that in Spain they also explode but the fact of not being that close to residences makes it harder to hear it.