I have a DataFrame to find the percentage of absolute difference between two sources in python. But when I use the below code, few of the columns are giving the -% (minus percentages)

I have checked the columns showing minus percentage datatypes are same in both the sources.

Can anyone help me to find out why?

    # Define the columns you want to process
columns = ['a', 'b', 'c', 'd']

# Create the results DataFrame
results_df = pd.DataFrame()

results_df['date'] = c_df['date']
results_df['id'] = c_df['id']

for col in columns:
    # calculating the absolute difference
    diff = np.abs(c_df[f'{col}_s1'] - c_df[f'{col}_s2'])

    # calculating mean for snowflake columns
    norm_diff = c_df[f'{col}_s1'].mean()

    # Avoid division by zero
    if norm_diff == 0:
        percentage = np.zeros(len(diff))
    else:
        # calculating percentage difference b/w the columns in both datasets
        percentage = (diff / norm_diff) * 100

    # Round the percentage_difference and add % symbol
    results_df[col] = [f"{round(diff)}%" for diff in percentage]

display(results_df)

And the results are something like this.

a b c d
0% 5% 10% -5%
10% 100% -50% 200%