> The guy who won the Nobel prize for giving himself an ulcer estimated it as 90%

That's worldwide. In developed countries the proportion is closer to 10 to 15% [1, 2]

[1] https://www.jwatch.org/na50875/2020/02/24/prevalence-h-pylor...

[2] https://pubmed.ncbi.nlm.nih.gov/31972622/