You have one year recorded for each distance, so do the histogram on the years. This doesn’t account for the distances (I’m not exactly certain how to fit them into a histogram by year in the absence of plot3, if you want to somehow include them), but will plot the histogram of the discoveries by year and decade.
The code:
fidi = fopen('jgillis16 oo20copy.txt', 'rt');
Dc = textscan(fidi, '%f%f', 'CollectOutput',1, 'TreatAsEmpty','~');
fclose(fidi);
D = cell2mat(Dc);
years = D(:,1);
distances = D(:,2);
yrbin = [min(years):max(years)]-0.5;
dcbin = 10*[floor(min(years)/10) : 1 : floor(max(years)/10)]+5;
figure(1)
subplot(2,1,1)
hist(years, yrbin)
grid
subplot(2,1,2)
hist(years, dcbin)
grid
