How can i make my results occupy less space on my plot?

In my code, my results on my plot occupies a lot of space. So i want to plot results skipping few steps and also add time label on each figure just as the picture below.

Here is my code. Can you help me please?

n = 101; % Number of grids
dy = 1.0 / (n-1);
Re = 100;              % Reynolds Number we define
phi_new = zeros(1,n);    % Storing velocity values for each point n==>which is y axis. And we defined no slip boundary condition here
phi_new(n) = 1;        % Second boundary condition
phi_old = phi_new;
dt = 5.0e-3;             % Maximum dt in order to keep the system stabile. Because we use Explicit Method
gamma = (dt/(Re*dy*dy)); % Calculated gamma value after discretization, for keeping equations simple
t = 50;                  % Time term

% Explicit FTCS

for i=1:dt:t+1
    plot(phi_new(1,:),1:n)
    for j=2:n-1
        phi_new(j) = phi_old(j) + gamma * (phi_old(j+1) - 2*phi_old(j) + phi_old(j-1)); % Discretized Equation 
    end
    phi_old = phi_new;
    hold on
end

[KSSV]

REduce your time step dt.

Answer 1

[KSSV]

n = 101; % Number of grids
dy = 1.0 / (n-1);
Re = 100;              % Reynolds Number we define
phi_new = zeros(1,n);    % Storing velocity values for each point n==>which is y axis. And we defined no slip boundary condition here
phi_new(n) = 1;        % Second boundary condition
phi_old = phi_new;
dt = 5.0e-3;             % Maximum dt in order to keep the system stabile. Because we use Explicit Method
gamma = (dt/(Re*dy*dy)); % Calculated gamma value after discretization, for keeping equations simple
t = 50;                  % Time term

% Explicit FTCS
i = 1:dt:t+1 ; 
m = length(i) ; 
iwant = zeros(m,n) ; 
for i=1:m
    iwant(i,:) = phi_new(1,:) ; 
    for j=2:n-1
        phi_new(j) = phi_old(j) + gamma * (phi_old(j+1) - 2*phi_old(j) + phi_old(j-1)); % Discretized Equation 
    end
    phi_old = phi_new;
end

Now the required data is saved into a matrix iwant. You can skip the rows and plot.