@name("Percent")
@url("https://en.wikipedia.org/wiki/Percentage")
@aliases(%: short, pct)
unit percent = 1e-02

@name("Permille")
@url("https://en.wikipedia.org/wiki/Per_mille")
@aliases(‰: short, permil, permill)
unit permille = 1e-03

@name("Parts per million")
@url("https://en.wikipedia.org/wiki/Parts-per_notation")
@aliases(ppm)
unit partspermillion = 1e-06

@name("Parts per billion")
@url("https://en.wikipedia.org/wiki/Parts-per_notation")
@aliases(ppb)
unit partsperbillion = 1e-09

@name("Parts per trillion")
@url("https://en.wikipedia.org/wiki/Parts-per_notation")
@aliases(ppt)
unit partspertrillion = 1e-12

@name("Parts per quadrillion")
@url("https://en.wikipedia.org/wiki/Parts-per_notation")
@aliases(ppq)
unit partsperquadrillion = 1e-15