keurig green mountain 's single-serve capsules in 2014 hit over $ 3 billion in us sales , it 's been revealed .
the company has also made $ 4.7 billion in revenue .
1/3 of homes in the us reportedly feature single-serve coffee machines .
keurig 's chief technology officer kevin sullivan has said ` single serve , i think , found the hidden need - the need that people did n't know they had '