On the Sectional and the WAC the Isogonic line near Petaluma (O69) shows 14*30" E. The airport info in the Garmin Pilot app, the Wing X Pro app, and the Variation at AirNav.com shows 16*E. AirNav shows it as 16*E(1985).
So why the variation? (pun intended)
Enquiring mind need to know!
Rolf
N9EY