There's no x value smaller than 0.5 in your inputs so it's unclear why you have a 10 in your first row of your table. I'm going to assume that your table is incorrect. There are more inconsistencies.
Your bin edges are also badly defined. What happens if x is 0.55, it's outside any of your bins. Same for y = 10.5. Normally you would define the end of bin 1 as x<0.5 and the start of bin2 as x>=0.5 (or x<=0.5 and x>0.5).
xy = xlsread('Scatter table.xlsx', '3:4');
histcounts2(x(1, :), y(2, :), [0 0.5 1.0 1.5 Inf], [0 5 10 15 Inf], 'Normalization', 'probability') * 100
