Table:
text: Parts-per notation
Uno
IUPAP's "uno" proposal
Coefficient Parts_per_example Uno_equiv_ Symbol_form Value_of_quantity
10 −2 2% 2 centiuno 2 cU 2×10 −2
10 −3 2 ‰ 2 milliuno 2 mU 2×10 −3
10 −6 2 ppm 2 microuno 2 µU 2×10 −6
10 −9 2 ppb 2 nanouno 2 nU 2×10 −9
10 −12 2 ppt 2 picouno 2 pU 2×10 −12

Question: What is the coefficient of 2 ppt under parts per notation?