link :
PCI was immediately put to use in servers, replacing MCA and EISA as the server expansion bus of choice. In mainstream PCs, PCI was slower to replace VESA Local Bus (VLB), and did not gain significant market penetration until late 1994 in second-generation Pentium PCs.
Eu arriscaria adivinhar que é daí que a discrepância vem: introdução original vs. adoção generalizada.
Editar: também:
Spec Year Change summary
PCI 1.0 1992 Original issue
PCI 2.0 1993 Incorporated connector and add-in card specification
Então eu acho que há algum debate sobre quando isso aconteceu.