Complex sentence: Until the 1990s, foreign domestic helpers mostly came from the Philippines; since then, to cope with the different demands of prospective employers, the percentages have been shifting away from Philippine helpers, in favour of Indonesian and other nationalities.
Split into simpler sentences: Until the 1990s, foreign domestic helpers mostly came from the Philippines. Since then, to cope with the different demands of prospective employers, the percentages have been shifting away from Philippine helpers, in favour of Indonesian and other nationalities.