I guess you have two options about how you're going to tell MATLAB about all those xlsx files - either you're going to construct the name based on the pattern (the year at the end of the filename) or you'll use dir to get a list of all the xlsx files.
Method 1: all the xlsx files in the current directory
fl = dir('*.xlsx'); % this assumes the current directory contains the xlsx files
% but that's generally a bad assumption
for i = 1:numel(fl)
data=readmatrix(fl(i).name);
plot(data(:,1),data(:,2),'LineWidth',3)
hold on
end
Method 2: using the pattern in the names
for i = 2014:2019
fn = "OS104BeachProfileData" + i + ".xlsx";
data=readmatrix(fn);
plot(data(:,1),data(:,2),'LineWidth',3)
hold on
end
