If the rate of income tax increases by 18%, net income decreases by 2%. What was the rate of income tax?

Given:
– The rate of income tax increases by 18%.
– The net income decreases by 2%.

1. The increase in income tax as a percentage of net income is:

\[ \frac{\text{Increase in income tax}}{\text{Net income}} = \frac{2\%}{18\%} = \frac{1}{9} \]

2. Let’s denote the income tax as \(x\) and the net income as \(9x\).

3. The total income is the sum of income tax and net income:

\[ \text{Total income} = x + 9x = 10x \]

4. The rate of income tax is the income tax divided by the total income:

\[ \text{Rate of income tax} = \frac{x}{10x} \times 100\% = 10\% \]

Conclusion:
The rate of income tax was 10%.