How to decrease the speed of a servo motor?

the servo has 1-2 ms duty cycle, and 20 ms refreshing frequency, bidirectional, non-continuous, 180 degree. It's Sg90. Using 100 Mhz Board clock and already divided it.

And this's a part of pwm code. For any help, I appreciate in advance

    process(CLK, DIR, EN)
 
constant time_high_stopped : INTEGER := (2000);--a square wave with a width of 2 milliseconds
        
        constant time_high_ccw : INTEGER := ( 3500); --counterclockwise
   --Anything wave above 2 ms will cause the servo to start to move counterclockwise. 
    --Anything below 2 will cause the servo to move clockwise. 
    constant time_high_cw : INTEGER := (500); --clockwise
    constant time_low : INTEGER := (20000);
       
   variable th_cntr : INTEGER range 0 to 3547 := 0; -- timehigh counter
   variable tl_cntr : INTEGER range 0 to 34719 := 0; --timelow counter
        
        begin
     if EN = '1' then 
    if rising_edge(CLK) then
      ---stopping the servo
   if DIR = "00" then  
      if tl_cntr <= time_low then
            tl_cntr := tl_cntr + 1;
       SERVO <= '0';
       elsif th_cntr <= time_high_stopped then
        th_cntr := th_cntr + 1;
       SERVO <= '1';      
          else
         tl_cntr := 0;
      th_cntr := 0;
    SERVO <= '0';
                                         
  end if;                             
---servo clock wise
elsif DIR = "01" then  
     if tl_cntr <= time_low then
        tl_cntr := tl_cntr + 1; 
      SERVO <= '0';
   
         elsif th_cntr <= time_high_ccw then
           th_cntr := th_cntr + 1;
         SERVO <= '1'; 
         else
         tl_cntr := 0;
         th_cntr := 0;
         SERVO <= '0';
        end if;
     ---servo counter clockwise
       elsif DIR = "10" then  
      if tl_cntr <= time_low then
      tl_cntr := tl_cntr + 1;
      SERVO <= '0';
                        
     elsif th_cntr <= time_high_cw then
        th_cntr := th_cntr + 1; 
       SERVO <= '1'; 
       else
      tl_cntr := 0;
      th_cntr := 0;
      SERVO <= '0';
       end if;                       
       end if;
     end if;
     end if; 
                
    end process;