Given the monthly returns that follow, find the R$2$

Month Portfolio Return $(\%)$ S&P $500$ Return $(\%)$

January $5\mathrm{.}005\mathrm{.}30$

February $-2\mathrm{.}40-3\mathrm{.}00$

March $-1\mathrm{.}70-0\mathrm{.}80$

April $3\mathrm{.}005\mathrm{.}00$

May $0\mathrm{.}700\mathrm{.}00$

June $-0\mathrm{.}90-0\mathrm{.}40$

July $0\mathrm{.}000\mathrm{.}50$

August $1\mathrm{.}703\mathrm{.}00$

September $1\mathrm{.}000\mathrm{.}10$

October $-3\mathrm{.}60-4\mathrm{.}30$

November $4\mathrm{.}002\mathrm{.}30$

December $0\mathrm{.}700\mathrm{.}60$

$0\mathrm{.}048$

$0\mathrm{.}9316$

$0\mathrm{.}8342$

$0\mathrm{.}8678$