Translate the following English sentence to French:
"Collective investment undertakings have for some time been the primary savings vehicle through which millions of ordinary citizens, without any specialist knowledge, have invested their life savings."
Les organismes de placement collectif constituent, depuis longtemps, le premier instrument d' épargne, l' instrument auquel des millions de citoyens, ni experts, ni professionnels, consacrent ou confient les économies d' une vie.