COUPEVILLE — Island County voters are staying true to history: Most voters have not yet mailed in their ballots for Tuesday’s special election.

Only one item is on the ballot for the May 17 special election: a $50 million bond proposal to fund an expansion of Whidbey General Hospital. The hospital hopes to get voter approval to build a new wing comprised of 39 single-bed rooms, along with space to expand existing hospital programs. The ballot measure requires a 60 percent supermajority to pass.

Past historical trends in Island County elections show an initial spike in ballot returns followed by a drop-off in ballot returns until the final week of the election. That trend is holding true for this week’s election.

Most ballots for the May 17 election were mailed the last week of April, and county election officials said 36,875 ballots were sent out.

The county has so far received a total of 13,370 ballots, not counting that will come in Monday’s mail.

The largest grouping of ballots were returned on May 3-5, with a total of 9,282 received (or 25 percent of ballots mailed). The most ballots received by the county on any single day was on May 3, when 3,925 ballots were returned.