Interpolating data whilst keeping subheadings

I have a large data set containing temperature and salinity data for the Celtic Sea and I'm having an issue with the interpolation. I used the following script to remove all the data i want removed however this gets rid of the dividing subheadings containing locations and times so i simply end up with a massive block text of data that is not discernible.

X=Sal_Celtic_Sea;

Xnew = X(X(:,1)>120,:);

Below is an example of the text i am working with. I want to keep the lines beginning with % but my script removes them all. Any help with this problem would be very much appreciated.

% -8.900000 58.016700 1964 2 22

     30.0000     34.2000
     50.0000     34.2030
     75.0000     34.2100
    100.0000     34.2280
    125.0000     34.2510
    150.0000     34.2600
 %       -7.483300       56.566700        1971           3          31
       .0000     34.7300
     10.0000     34.7330
     20.0000     34.7370
     30.0000     34.7400
     50.0000     35.0200
     75.0000     35.1370
    100.0000     35.1930
    125.0000     35.2240
    150.0000     35.2460