I'm sure it does but there is always a trade-off area where the two field strengths are equal or similar. My guess would be Kent's East Hill area.
A few weeks ago I listened to 97.7 while riding the bus up to the airport, and found that at 518 up the hill to International Blvd and International Blvd across 518 the station is unlistenable from the booster interfering with the main station. So there you go. Right there at the main Sea-Tac car rental facility, where visitors are deciding which stations to program in, they might skip over 97.7 entirely.