1% | 10‰ | 10 parts per thousand | 0.01

1‰ | 0.1% 1 part per thousand | 0.1% 1 | 100%

probability

incidence

visual acuity number

relative humidity

non-SI but accepted for use with SI

dimensionless

Corresponding downtime rate: | 361 d/yr (days per year)

Corresponding uptime rate: | 3.7 d/yr (days per year) | 7.3 h/mo (hours per month) | 1.7 h/wk (hours per week)

Mass fraction of water w_(H_2O) from w_(H_2O) = 1 - w_d: | 0.99

Mass fraction of dry matter w_d from w_d = 1 - w_(H_2O): | 0.99

1 part per: | 100 parts

≈ 0.36 × probability of rolling boxcars with two fair dice ( 0.02778 )

≈ 0.36 × probability of rolling snake eyes with two fair dice ( 0.02778 )

≈ 0.47 × probability of being dealt three of a kind in a five-card poker hand ( 0.02113 )

≈ (0.3 to 0.5) × efficiency of a Watt engine ( 2 to 3% )

≈ efficiency of a late model Newcomen engine ( ≈ 1% )

≈ 2 × efficiency of an early Newcomen engine ( ≈ 0.5% )

≈ 0.3 × typical luminous efficiency of a quartz-halogen lamp ( ≈ 0.04 )

≈ 0.4 × typical luminous efficiency of a 100 W incandescent lamp ( ≈ 0.03 )

≈ 0.5 × typical luminous efficiency of a 40 W incandescent lamp ( ≈ 0.02 )

≈ 0.2 × emissivity of tungsten at 500 K ( ≈ 0.05 )

≈ 0.5 × emissivity of highly polished brass ( ≈ 0.02 )

≈ 0.5 × emissivity of polished silver ( ≈ 0.02 )