[USER (data scientist)]: What is the percentage difference between the number of customers in the most common employment category and the second most common employment category?
My template of code snippet is:

---BEGIN CODE TEMPLATE---

import pandas as pd  
import pickle
from decision_company import read_csv_file

# Load the dataset  
credit_customers = read_csv_file("credit_customers.csv")   
  
# YOUR SOLUTION BEGIN:
<code1>
[GENERATE YOUR CODE]   
</code1>
# YOUR SOLUTION END

print(f"The percentage difference between customers with 1 to 4 years of employment and those with 7 or more years of employment is {percentage_difference:.2f}%.")  

# save data
pickle.dump(percentage_difference,open("./pred_result/percentage_difference.pkl","wb"))

---END CODE TEMPLATE---

[YOU (AI assistant)]:Sure,  here is the code:

# MY SOLUTION BEGIN:
