Top 10 Countries With the Most Metal Bands Per Capita (2016)
This is a list of the highest density of metal bands per capita. The data from http://i.imgur.com/zRDq4.png is from 2012 and not accurate enough to create a list. Therefore, I collected more recent data from sites like the Metal Archives.Some information:
I excluded tiny countries with less than 100,000 inhabitants because adding or removing just one band would significantly affect the ranking, and the Metal Archives are not that precise, in my opinion.
Liechtenstein would probably rank 4th or 5th after or before Norway, and Monaco would be between Greece and Denmark.
Furthermore, here are the contenders (the metal bands per capita ratios are very close, though):
11. Austria
12. Germany
13. Czech Republic
14. Slovenia
15. Portugal
16. Switzerland
17. Hungary
18. Belgium
19. Chile
20. Italy
21. Slovakia
22. Canada
23. Croatia
24. Australia
25. Poland
26. USA
27. New Zealand
28. France
29. United Kingdom
30. Spain

Finland is the number one with around 3,400 metal bands per 5.5 million people living there! The metal scene is quite established here and many are internationally well known.
Finnish metal is most popular for their Power Metal, Melodic Death Metal, and Folk Metal.
Some of the best-known bands are: Children Of Bodom, Nightwish, Wintersun, Ensiferum, Insomnium, Lordi, Kalmah, Finntroll, Sonata Arctica, Amorphis, Demigod, Stratovarius, Korpiklaani, Omnium Gatherum, Ghost Brigade, Swallow the Sun, Eternal Tears of Sorrow, Sinergy, and Apocalyptica...
I love this list and I'm not surprised Finland is at number one! I wrote somewhere that probably 50% of the Finns are in metal bands and the other 50% are metal fans. Of course, it was a joke, but it wasn't far from the truth.
I would like to point out that Finland has a very high living standard and has often been the number one best country to live in, according to different objective indicators. I don't think these indicators included the great metal scene though, haha.
Best countries ever. Love all Nordic countries from Chile.

Sweden is number 2 with around 4,080 metal bands and 9.8 million people. Like in Finland, the metal scene is well established and internationally appreciated.
Swedish metal is most popular for... well, you guessed it: Melodic Death Metal. Other styles are also prominent here, but not as Melodic Death Metal.
Some of the best-known bands are: Opeth, At The Gates, In Flames, Dark Tranquillity, Meshuggah, Dissection, Dismember, Bathory, Entombed, Watain, Hypocrisy, Amon Amarth, Arch Enemy, HammerFall, Therion, and General Surgery.
This list proves one of my personal observations on metal music: metal is popular in the developed countries. Metal isn't popular in Africa. Metal isn't popular in the Southern states of the US - there you have blues, and so on.
Scandinavian countries have well-developed societies and well-developed metal scenes at the same time. I don't think this is a coincidence.

This is a very small country with around 330,000 people. Still, they have slightly more than 100 metal bands, which puts them on number 3 of metal bands per capita.
I'm not so informed about Icelandic Metal, so I can't tell you much about it, but I heard bands like: Zhrine, Sólstafir, Svartidaudi, Severed Crotch, and Wormlust are well received.


Now we come to countries, where metal isn't that well established like 1-4, but still have a big scene. Greece has nearly 11 million inhabitants and around 1,770 metal bands.
Some of the best-known bands are: Septic Flesh, SlavEatGod, Nightrage, Rotting Christ, and Nightfall.

Artillery anyone? They're from Denmark.

Estonia is a rather small country and has about 1.3 million inhabitants & 180 bands, but I never heard of any band from there. Surely there is a big metal fan base though.
After some research, I found some bands, which are merely known in the underground scene:
Metsatöll, Paean, Talbot, Herald

Luxembourg is a small country with around 563,000 people there and 80 metal bands. There are definitely not much, but still some decent bands.
I don't know much about metal from Luxembourg, but these seem to be well received:
Scarred, Scarlet Anger, Abstract Rapture, Funerarium

Malta is also a very small country with around 445,000 inhabitants and 60 metal bands.
Some recognized bands are: Beheaded, Abysmal Torment, Weeping Silence, Slit

The Netherlands has around 17 million people and 2,100 metal bands. Since the country is bigger, the metal scene is also bigger, although the country isn't ranked very high here.
Some of the better-known bands are Epica, Pestilence, Within Temptation, After Forever, Delain, The Gathering, Sinister, God Dethroned, Gorefest, Legion of the Damned, The Monolith Deathcult, and Heidevolk.