After dicussing this at great length and having other folks there so that you unquestionably have informed consent and a means to essentially have multiple trip-sitters, have an opioid-naïve person you know, or you if you do not take narcotics, take one of someone's leftover DF-118s or Tikes or Vikes or itty bitty Codeine HCl tabs if they are in no pain and in a reasonably positive state of mind -- it will make them nauseous, maybe a little panicky, give them a headache and make them itchy, and it will do nothing for them subjectively, and they will not want to repeat it, because narcotics are much more subtle than C-Jam or alcohol or weed or meth, Shabu, caffeine, nicotine . . . There are endocrine, metabolic, neurological and perhaps psychological reasons for this, enough to add up to it being a near-determined outcome.
Therefore the 23 per cent overall figure seems within the realm of possibility if one believes that there really are people who take drugs because they think they are cool, because of "peer pressure" and the like, imitation, curiosity . . . Someone who knows that smack is a painkiller and euphoriant who seeks it out, especially if they cannot get something else like hydrocodone or oxycodone, is going to have different results.
A table from page 7 of The Chemistry of Mind Altering Drugs, by Daniel Perrine (1996) cites a survey of doctors involved in addiction treatment (the table is also reproduced in You Will Die: The Burden of Modern Taboos by Robert Arthur (Feral House, 2012) Page 226, and the 7th Edition (October 2017) of Inside Narcotics, Page 13) gives the addictiveness score of heroin, a different measure taking several things into account, as 80 on a scale from 0 to 100, about in the middle of the table and tied with snorted Crank, compared to 99 for nicotine, 98 for Ice, 97 for crack, 92 for IV Crystal Meth, 83 for Valium, 81 for alcohol, 82 for Reds, 71 for C-Jam, 70 for caffeine, 57 for Angel Dust, 22 for Weed, 20 for E, 19 for Shrooms, 16 for Acid, 15 for Big Chief . . . my guess is that if poppers were on this table it may be like 36 or thereabouts, White Tornado 95, fentanyl 20 or so, clomethiazole would be in the 60s somewhere, M would be 75 or so, codeine 50, DHC 70, hydrocodone 83, nicomorphine 80, dextromoramide 80, Ludes 85, air 100, methylphenidate 90, White Crosses 88, pentazocine 15, Ts & Blues 60, dextropropoxyphene 58, tripelennamine 50, Blue Velvet 85, model aeroplane glue 17, petrol 16, Ortho Weed B-Gon 8, Tabasco Sauce on your pecker 5, but your results may vary . . .