To find the total employment for sheet metal workers in 2006 based on the 2016 employment figure and the percentage increase, we can use the following formula:
\[ \text{Total Employment in 2006} = \frac{\text{Total Employment in 2016}}{1 + \text{Percentage Increase}} \]
The percentage increase of 6.3% can be expressed as a decimal, which is 0.063. Therefore, we calculate:
\[ \text{Total Employment in 2006} = \frac{201,000}{1 + 0.063} = \frac{201,000}{1.063} \]
Now we can calculate that:
\[ \text{Total Employment in 2006} \approx \frac{201,000}{1.063} \approx 189,000 \]
Thus, the total employment in 2006 is approximately 189,000.
So the answer is: d. 189,000