Complex sentence: Total economic losses from the disaster were tremendous, amounting to SI $787.3 million (US $107.8 million) or roughly 9.2 percent of the country's gross domestic product.
Split into simpler sentences: Total economic losses from the disaster were tremendous, amounting to SI $787.3 million (US $107.8 million). This total equates to 9.2 percent of the country's gross domestic product.