我正在尝试将趋势线（线性平均值）添加到绘图中。我想在一个图中为 11 条单独的线设置一条平均趋势线。我的情节是这样的：
现在我想要一（1）个彩色线条的平均趋势。两条灰线是最大值和最小值，形成平均趋势线时不考虑壳。彩色线的唯一趋势线。我的数据如下所示：
jahr beob werex_00 werex_11 werex_22 werex_33 werex_44 werex_55 werex_66 werex_77 werex_88 werex_99 Min Max
1961 NA NA NA NA NA NA NA NA NA NA NA -18,6304 61,1809
1962 NA NA NA NA NA NA NA NA NA NA NA -11,9439 87,5546
1963 NA NA NA NA NA NA NA NA NA NA NA -15,5266 82,2700
1964 NA NA NA NA NA NA NA NA NA NA NA -40,0319 85,2906
1965 NA NA NA NA NA NA NA NA NA NA NA -34,3038 94,9024
1966 -3,8771 8,3257 24,8513 13,5184 21,0853 15,6732 1,8496 -8,4903 2,1629 8,2024 16,1356 -31,3819 92,7969
1967 -9,4982 11,3976 23,0892 13,9196 16,8335 17,2100 2,9570 -10,1167 3,9671 7,2876 10,6471 -7,5067 110,6196
1968 -11,2913 11,4993 18,3050 8,0152 13,9073 16,8016 4,7250 -12,9246 2,6713 5,4357 3,5107 -51,2107 138,7448
1969 2,6362 9,1087 19,9564 6,0345 3,8747 11,6780 2,5116 -13,4089 4,3353 0,3998 3,1798 -30,3322 42,1300
1970 6,6531 2,0238 20,5422 2,3972 0,4017 11,1036 5,0465 -10,2958 8,3485 -2,1658 4,6128 -11,5068 44,3986
1971 -1,7923 3,0214 18,7542 2,5401 -2,5444 8,3054 1,8535 -10,1233 8,3663 2,0204 1,9454 -22,3762 95,3033
1972 -1,1383 0,1923 21,6838 -1,2288 -4,1658 4,4113 2,5008 -7,6908 9,6488 2,3338 0,7093 -29,0978 31,1931
1973 -3,9827 2,7288 19,6430 -0,1119 -3,9149 3,1060 -3,5426 -5,1332 3,9206 1,2295 -6,9931 -30,3709 44,2175
1974 -5,6800 -0,2600 13,2311 1,2855 -11,7234 -8,2399 -5,7620 -4,3448 8,3248 -0,5500 -5,6376 -44,4719 143,3977
1975 -0,6020 4,4594 13,4312 1,8103 -11,7964 -11,2020 -2,9454 -0,8192 6,8733 -1,6069 -7,5460 -27,5719 46,5896
1976 9,0707 4,0255 12,8539 0,5613 -9,0911 -14,6242 -2,0957 0,3028 4,2881 -4,2491 -1,5111 -36,0912 22,2878
1977 6,2822 7,5568 3,2908 1,3875 -9,0588 -14,0812 -2,3505 2,0262 2,7041 -1,6706 2,6180 -13,8766 99,9908
1978 8,9476 11,4753 -0,1546 0,4597 -7,2769 -9,6268 -0,7031 1,2291 -0,2699 -2,7092 3,2059 -19,4729 79,3319
1979 8,9790 6,8742 -3,7599 -1,0170 -4,2174 -11,7519 -2,6872 4,4382 0,2518 -3,8938 4,6531 -39,0920 78,4498
1980 -0,7982 5,3090 -7,1990 0,3482 0,7074 -3,8802 -1,6347 5,7365 -2,5424 -4,5144 4,2867 -43,8048 95,6593
......
现在我在为ggplot使用melt（）之后绘制日期。熔化将数据转换为：
Jahr Projektion value
1961 beob NA
1962 beob NA
1963 beob NA
1964 beob NA
1965 beob NA
1966 beob -3,877072807
1967 beob -9,498158353
1968 beob -11,29127163
1969 beob 2,636225556
… … …
1961 werex_00 NA
1962 werex_00 NA
1963 werex_00 NA
1964 werex_00 NA
1965 werex_00 NA
1966 werex_00 8,32566516
1967 werex_00 11,39762871
1968 werex_00 11,49932052
1969 werex_00 9,108708251
… … …
现在我绘制了数据（上图）：
Projektionen_Farben<-c("#000000","#00EEEE","#EEAD0E","#006400","#BDB76B","#EE7600","#68228B","#8B0000","#1E90FF","#EE6363","#556B2F","#D6D6D6","#D6D6D6")
GJm11_Grundwasserneubildung_Jahr_norm_druckreif <- melt(GJm11_Grundwasserneubildung_Jahr_norm,na.rm = FALSE, id.vars="jahr")
names(GJm11_Grundwasserneubildung_Jahr_norm_druckreif)<-c("Jahr","Projektion","value")
GJm11_Grundwasserneubildung_Jahr_norm_druckreif$Jahr <- as.numeric(factor(Jahr))
ggplot(GJm11_Grundwasserneubildung_Jahr_norm_druckreif,aes(x=Jahr,y=value,color=Projektion,group=Projektion))+
geom_line(size=0.8) + xlab("Jahr") + ylab("Grundwasserneubildung [mm/a]") +
ggtitle("Grundwasserneubildung") + theme_bw() +
scale_x_continuous(breaks=c(1961,1980,2000,2020,2040,2060,2080,2100)) +
theme(axis.title=element_text(size=15,vjust = 0.3,face="bold"), title=element_text(size=15,vjust = 1.5,face="bold")) +
scale_colour_manual(values = Projektionen_Farben) + coord_cartesian(xlim = c(1961, 2100)) +
geom_ribbon(data=GJm11_Grundwasserneubildung_Jahr_norm,aes(x=jahr,ymin=Min,ymax=Max),inherit.aes=FALSE,alpha=0.1,color="grey30")
那么我怎样才能得到彩色线的平均趋势线呢？我也想知道，是否有办法添加某些时间段（如 1961-2000、2021-2050 和 2071-2100）的平均趋势线，只是为了比较这段时间的趋势？
希望有人能给我一个提示。
