To attract and retain qualified and experienced teachers and school employees, maintain educational programs that enhance student achievement, and reduce the size of targeted classes, shall the Palo Alto Unified School District be authorized to: levy an annual tax of $293 per parcel for 5 years, exempting upon application parcels owned by and principal residences of persons 65 years or older; and also, raise the District's annual appropriations limit in an amount equal to the tax for that year?