I'd wager those hackers were 15 years old, because anyone older would have made more money

The hackers 3 bitcoin addresses are registering just under 15 bitcoins in total - they hacked far and wide (with a possible mass death rate) for about £30k.
What a bunch of pricks.
The 'epidemic' has been quelled by a 22 year old who still lives at home - he noticed the bot referenced an obscure web address that was available to buy... so he bought it.
Turns out it was a kill switch.
Not that it will help the NHS, or my local doctors surgery, who have had files scrambled already. There is suggestion that paying the ransom won't fix the encryption, that the hackers are just trawling for vulnerable machines owned by people with the wherewithal to pay in Bitcoin, so by definition folks who run outdated software on a public network (ie naive) who have the ability to counter sign any data that the hackers will presumably release upon receipt of the money... even though they won't know who you are because a generic BTC address has been used (which means the hackers won't know who you are even if you pay them).
They are looking for very gullible, out of date computer users who know how to encrypt and digitally sign data, and who are willing to pay people who have not the power to decrypt their scrambled files.
And in the hunt for this rare beast they were prepared to risk nuclear meltdown and more incalculable personal tragedy than one dare to imagine.
Those addresses are:
https://blockchain.info/address/13AM4VW2dhxYgXeQepoHkHSQuy6NgaEb94
https://blockchain.info/address/12t9YDPgwueZ9NyMgw519p7AA8isjr6SMw
https://blockchain.info/address/115p7UMMngoj1pMvkpHijcRdfJNXj6LrLn