DF = data.frame(
    year=as.factor( 2000:2003 ),
    eastern=c( 1.1, 1.3, 2.9, 3.5 ),
    north_central=c( 0.1, 0.8, 1.1, 1.3 ),
    southwest=c( 0.9, 1.0, 1.4, 1.5 )
)

library(reshape2)
DF_melt = melt(DF, id.vars=c('year'), value.name='percent_increase', variable.name='region')