No predictions loaded for 2000. This site serves NOAA predictions from its own store, and this period has not been fetched for Unalaska yet. Nothing is estimated or interpolated in its place. NOAA's own page for the station has the official table: tidesandcurrents.noaa.gov.
tidealmanac.site/us/ak/unalaska-9462620/2000
Unalaska, AK tide table 2000 (printable) · Tide Almanac