a. The average rate of change for \( P \) between 1992 and 2000 is calculated as follows:
\[ \text{Average rate of change} = \frac{P(2000) - P(1992)}{2000 - 1992} \]
\[ \text{Average rate of change} = \frac{45.0 - 42.7}{2000 - 1992} \]
\[ \text{Average rate of change} = \frac{2.3}{8} \]
\[ \text{Average rate of change} = 0.2875 \]
So, the average rate of change for \( P \) between 1992 and 2000 is \( 0.2875\% \) per year.
b. Look for two consecutive years where \( P \) decreases. Let's take \( r_1 = 2004 \) and \( r_2 = 2008 \).
\[ \text{Average rate of change} = \frac{P(2008) - P(2004)}{2008 - 2004} \]
\[ \text{Average rate of change} = \frac{48.4 - 45.0}{2008 - 2004} \]
\[ \text{Average rate of change} = \frac{3.4}{4} \]
\[ \text{Average rate of change} = 0.85 \]
So, the average rate of change for \( P \) between 2004 and 2008 is \( 0.85\% \) per year.
c. Look for two consecutive years where \( P \) increases. Let's take \( r_3 = 1996 \) and \( r_4 = 2000 \).
\[ \text{Average rate of change} = \frac{P(2000) - P(1996)}{2000 - 1996} \]
\[ \text{Average rate of change} = \frac{34.5 - 33.1}{2000 - 1996} \]
\[ \text{Average rate of change} = \frac{1.4}{4} \]
\[ \text{Average rate of change} = 0.35 \]
So, the average rate of change for \( P \) between 1996 and 2000 is \( 0.35\% \) per year.