To Workspace returns shorter array than input

Hello! I have problem in simulink where I have input 'u_sim' in format 100x2 matrix with discrete values:

x = 0:99;
u=5*cos(3*pi*fp1/fsr*x)+cos(2*pi*fs1/fsr*x)+2*cos(pi*fp2/fsr*x)+cos(4*pi*fs2/fsr*x);
u_sim=[x;u]';

and I have simulink model that looks like this:

When I finish simulation, lasting 100s, To Workspace block returns to workspace u_sim_out variable with format 51x1 double. I've expected 100x1 format value. Why is it happening and how can I fix it? I use R2016a matlab version. If any other information needed I will provide it. Thanks in advance!