Oregon has long had one of the most volatile tax systems in the country. When in 1990 Measure 5 limited property taxes to $15 per $1,000 real market value, the result was a stronger reliance on corporate and income taxes to fund state programs like education, public health and public safety.That, combined with Oregonians’ aversion over the past decades to anything resembling a sales tax, has meant that when economic times are hard here, revenue drops, sometimes precipitously, and legislators must slash the budget.