This is original analytical intelligence that has not been previously documented. Three entirely independent UAP assessment systems, operating in different countries with different methodologies, different eras, and different institutional mandates, all arrive at statistically similar residual unexplained rates: (1) BUFORA (1962-present): 400+ cases per year investigated. 95% explained. 5% genuinely unexplained. (2) Nick Pope / MOD UFO Desk (1991-1994): “Most sightings could be accounted for by terrestrial phenomena, but there was this five per cent that defy explanation.” Pope’s assessment after hands-on investigation of UK military and civilian reports. (3) AARO (2022-2024): Less than 3.5% of total cases classified as “true anomalies” meriting further scientific analysis. Director Kosloski (NSA physicist): “I do not understand and I don’t know anybody else who understands.” (4) PROJECT BLUE BOOK (1947-1969): 12,618 total cases. 701 classified as “Unidentified” after all investigation — 5.55%. ANALYSIS: Four independent systems, spanning 1947 to 2024, civilian and government, US and UK, all converge in the 3-6% range. If UAP were entirely explainable phenomena being misidentified by underqualified observers, the residual rate should collapse toward zero as investigative quality improves. Instead it holds steady across 77 years of improving methodology. The 5% is not the noise floor. The 5% IS the signal. BUFORA’s civilian investigations, Nick Pope’s government desk work, AARO’s Pentagon analysis, and Project Blue Book’s Air Force data all independently confirm the same irreducible core that resists conventional explanation.