text: Based on the results of , the IAEA defined the delta scale with SLAP at −55.5‰ for O and −428‰ for H. That is, SLAP was measured to contain approximately 5.55% less oxygen-18 and 42.8% less deuterium than does VSMOW, and these figures were used to anchor the scale at two points. Experimental figures are given below.
  * H / H – , , about 1 in 11230 atoms
  * H / H –  = , measured on 16 September 1976, about 1 in 2.6710 atoms
  * O / O – , , about 1 in 528 atoms
  * O / O – , about 1 in 3700 atoms