How can I find the actual retail vs. institutional share allocation percentage for a completed IPO?

When a company goes public, the split between the institutional tranche and the retail tranche is often discussed in generalities (e.g., the standard 90/10 rule of thumb). However, the actual breakdown can vary significantly from deal to deal, especially for highly anticipated or tech-focused IPOs where fintech apps or retail-focused brokerages secure specific allocations. For a specific, already completed IPO, where exactly can an individual investor find the verified, final percentage or numbe