We're dividing 66371590 by 19 
The aim is to understand the frequency of 19 in 66371590.

Advancing to step 1:
If we divide 6 by 19, we get 0 and a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Include the next digit (6) from the dividend after 6, then repeat: 66 / 19

Going ahead to step 2:
19 can be fit into 66 3 times, resulting in a remainder of 9.
Put 3 as the next digit of the answer. 
Result so far: 3.0
Subtract 57 from 66 to get 9.
Grab the next digit (3) from the dividend, add it to 9, then carry on: 93 / 19

Step 3:
The number 19 fits into 93 4 times, leaving a remainder of 17.
The next digit of our result is 4. 
Result so far: 34.0
The remainder is 17 after subtracting 76 from 93.
Bring next digit (7) of the dividend behind the 17 and repeat the process: 177 / 19

Let's proceed to step 4:
When dividing 177 by 19, we get 9 with a remainder of 6.
Use 9 as the next digit of our solution. 
Result so far: 349.0
Deduct 171 from 177 and we're left with 6.
Fetch the next digit (1) from the dividend, attach it to 6 and continue: 61 / 19

Step 5:
19 goes into 61 3 times with a remainder of 4.
The number 3 becomes the next digit in our result. 
Result so far: 3493.0
Subtract 57 from 61 to get 4.
Append the next digit (5) from the dividend to 4 and continue with: 45 / 19

Let's proceed to step 6:
When dividing 45 by 19, we get 2 with a remainder of 7.
Record the quotient 2 as the next digit in the result. 
Result so far: 34932.0
The remainder is 7 after subtracting 38 from 45.
Fetch the next digit (9) from the dividend, attach it to 7 and continue: 79 / 19

Advancing to step 7:
The number 19 fits into 79 4 times, leaving a remainder of 3.
The number 4 becomes the next digit in our result. 
Result so far: 349324.0
Subtracting 76 from 79 leaves us with 3.
Take the next digit (0) from the dividend and append it to 3, then repeat: 30 / 19

On to step 8:
The number 19 fits into 30 1 times, leaving a remainder of 11.
Put 1 as the next digit of the answer. 
Result so far: 3493241.0
Deduct 19 from 30 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 9:
19 goes into 110 5 times with a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 3493241.5
If we subtract 95 from 110, we get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 10:
The number 19 fits into 150 7 times, leaving a remainder of 17.
Use 7 as the next digit of our solution. 
Result so far: 3493241.57
If we subtract 133 from 150, we get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Step 11:
19 goes into 170 8 times with a remainder of 18.
Write down 8 as next digit of the result. 
Result so far: 3493241.578
Deduct 152 from 170 and we're left with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 12:
19 goes into 180 9 times with a remainder of 9.
The number 9 becomes the next digit in our result. 
Result so far: 3493241.5789
The remainder is 9 after subtracting 171 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Moving on to step 13:
When dividing 90 by 19, we get 4 with a remainder of 14.
Put 4 as the next digit of the answer. 
Result so far: 3493241.57894
Subtracting 76 from 90 leaves us with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Let's proceed to step 14:
If we divide 140 by 19, we get 7 and a remainder of 7.
Put 7 as the next digit of the answer. 
Result so far: 3493241.578947
Subtract 133 from 140 to get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

On to step 15:
19 can be fit into 70 3 times, resulting in a remainder of 13.
The next digit of our result is 3. 
Result so far: 3493241.5789473
If we subtract 57 from 70, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Advancing to step 16:
If we divide 130 by 19, we get 6 and a remainder of 16.
Write down 6 as next digit of the result. 
Result so far: 3493241.57894736
If we subtract 114 from 130, we get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

After the division, we end up with 3493241.57894736 and a remainder of 1.6e-08.