Translate the following English sentence to French:
"If 23% of Europe' s population is over 65 years old today, this figure will have reached 40% by 2025, and the proportion of four working people to every retired person will have become two working people to every retired person by 2020."
Si, aujourd'hui, 23 % de la population européenne a plus de 65 ans, ce chiffre sera de 40 % en 2025, et la proportion de quatre travailleurs pour un retraité passera à deux travailleurs pour un retraité en 2020.