ɪn nˈaɪntiːnhˈʌndɹɪd ˈeɪɾi nˈaɪn, ðə mˈeɪn bˈɪldɪŋ wʌz ɛkspˈændᵻd wɪð ɐ ɐdˈɪʃən, wɪððə mjuːzˈiəmz ɐtˈɛndəns ɹˈiːtʃɪŋ wˈʌnhˈʌndɹɪd,zˈiəɹoʊzˈiəɹoʊ zˈiəɹoʊ pɜː jˈɪɹ.
In 1989, the main building was expanded with a  addition, with the museum's attendance reaching 100,000 per year.