To find Bob's family's annual health insurance premium, we need to first determine the total amount that Bob pays from his paychecks in a year.
Since Bob has 26 pay periods and $185.30 is withheld from each paycheck, we can calculate the total amount Bob pays annually:
\[ \text{Total withheld from paychecks} = \text{Amount per paycheck} \times \text{Number of paychecks} \]
\[ \text{Total withheld from paychecks} = 185.30 \times 26 = 4,817.80 \]
This amount represents 77% of the total premium (since his employer covers 23% of the premium, Bob covers the remaining 77%). Let \( P \) be the annual health insurance premium. The relationship can be expressed as:
\[ 0.77P = 4,817.80 \]
To find \( P \), we can solve for it:
\[ P = \frac{4,817.80}{0.77} \]
Calculating \( P \):
\[ P \approx 6,256.88 \]
Thus, Bob's family's annual health insurance premium is approximately:
\[ \boxed{6,256.88} \]