distance/mm density/cm^-3 14 892272800000000.0 16 891030000000000.0 18 890409300000000.0 20 889560100000000.0 22 889215900000000.0 24 889060600000000.0 26 888768400000000.0 28 888506900000000.0 30 888416300000000.0 32 888519600000000.0 34 888456100000000.0 36 888432100000000.0 38 888548800000000.0 40 888267000000000.0 42 888211400000000.0 44 888108500000000.0