TAI in this form was synchronised with Universal Time at the beginning of 1958, and the two have drifted apart ever since, due primarily to the slowing rotation of the Earth.
tˌiːˌeɪˈaɪ ɪn ðɪs fˈɔːɹm wʌz sˈɪŋkɹənˌaɪzd wɪð jˌuːnɪvˈɜːsəl tˈaɪm æt ðə bɪɡˈɪnɪŋ ʌv nˈaɪntiːnhˈʌndɹɪd fˈɪfti ˈeɪt, ænd ðə tˈuː hæv dɹˈɪftᵻd ɐpˈɑːɹt ˈɛvɚ sˈɪns, dˈuː pɹaɪmˈɛɹᵻli tə ðə slˈoʊɪŋ ɹoʊtˈeɪʃən ʌvðɪ ˈɜːθ.