c	m	n
Sweden	2014	454088
Nordic countries	2014	46019
European countries	2014	25068
Other countries	2014	17100
Sweden	2015	485509
Nordic countries	2015	44467
European countries	2015	26994
Other countries	2015	14261
Sweden	2016	542091
Nordic countries	2016	51562
European countries	2016	33767
Other countries	2016	16360
Sweden	2017	560829
Nordic countries	2017	56723
European countries	2017	34139
Other countries	2017	23839
Sweden	2018	548372
Nordic countries	2018	56441
European countries	2018	44513
Other countries	2018	34174

数据表如图，代码如下：

ggplot(summary,aes(x=m,y=n,fill=c,label=n))+
  geom_bar(stat="identity",position="dodge")+
  theme_wsj(color="white")+
  scale_fill_wsj("rgby", "")+
  scale_y_continuous(breaks = seq(50000,800000,100000))+
  theme(axis.ticks.length=unit(0.5,'cm'))+
  guides(fill=guide_legend(title=NULL))+
  theme(axis.title = element_blank())
  geom_text(aes(y = n + 0.05), position = position_dodge(0.9), vjust = -0.5)


数据出图如下，问题是，如何将柱图在每年内按降序排列？