The year where the qualifying score was 15.150 is 2008.0.
[['Uneven Bars', 'FINAL-SCORE', '15.550'], ['U.S. Championships', 'EVENT', 'Uneven Bars'], ['15.550', 'QUALIFYING_SCORE', '15.150'], ['U.S. Championships', 'YEAR', '2008'], ['U.S. Championships', 'LOCATION', 'Boston'], ['6', 'QUALIFYING_RANK', '6'], ['Uneven Bars', 'FINAL-RANK', '6']]