Probably better than 15%...
My better half (Gold) has been upgraded more than half the time in/out of LV this year. LV flights are headed to/from a leisure deestination and normally don't carry a high percentage of gold/platinum elites except for a few conventions (CES comes to mind), plus even the conventions are whittled back due to the current economic climate.
If it doesn't occur 3 days out, don't assume you're not getting it. Half of her upgrades didn't come in at the 3-day mark. Good luck...