The other 80% has to be produced by oil wells using enhanced oil recovery techniques like steam-assisted gravity drainage.
ðɪ ˈʌðɚɹ ˈeɪɾi pɚsˈɛnt hɐz təbi pɹədˈuːst baɪ ˈɔɪl wˈɛlz jˈuːzɪŋ ɛnhˈænst ˈɔɪl ɹᵻkˈʌvɚɹi tɛknˈiːks lˈaɪk stˈiːmɐsˈɪstᵻd ɡɹˈævᵻɾi dɹˈeɪnɪdʒ.