Step 1 :The point estimate for the population proportion is calculated by dividing the number of successes (in this case, the number of adults who have donated blood) by the total number of observations (in this case, the total number of adults surveyed). So, we need to divide 423 by 2323.
Step 2 :\(\frac{423}{2323} = 0.18209212225570384\)
Step 3 :Rounding to three decimal places, we get 0.182.
Step 4 :Final Answer: The point estimate for the population proportion of adults in the country aged 18 and older who have donated blood in the past two years is \(\boxed{0.182}\).