Resale royalty right continues to subsist in relation to an artwork until the end of 70 years after:
(a) if there is only one artist of the artwork--the end of the calendar year in which the artist dies; or
(b) if there is more than one artist of the artwork then, in relation to the proportion of the resale royalty right held by or through a particular artist--the end of the calendar year in which the artist dies.