Plot trend lines and equation for multiple variable in ggplot

i am trying to plot trend lines and equation with R square for three variable (SA,SA1,SA2) using ggplot geom_smooth(). While plotting three variables i get only one trend line. What might be the cause and solution of such plot? DATA LINK (3 trend lines + 3 equation with R^2)

library(ggplot2)
test <- read.xlsx2("filepath/test.xlsx", 1, header=TRUE)
> test
   year           SA          SA1         SA2
1  2008 1.409155e+15 3.632740e+17 4.06998e+15
2  2009 1.533598e+15 3.767342e+17 4.05015e+15
..
..
10 2017 1.761596e+15 3.581407e+17 3.03403e+15
11 2018 1.677707e+15 3.428239e+17 3.15862e+15
dput(test)
structure(list(year = structure(1:11, .Label = c("2008", "2009", 
"2010", "2011", "2012", "2013", "2014", "2015", "2016", "2017", 
"2018"), class = "factor"), SA = c(1409155313839800, 1533598052716370, 
1524727969175020, 1583941250825040, 1597021832828680, 1549362217661020, 
1607700438214130, 1592107298305410, 1735331260744350, 1761596167580970, 
1677707298223350), SA1 = c(363273957183114432, 376734225895083200, 
355896023882281984, 368398075167704192, 367791249493954048, 360257619620708800, 
360061958768956736, 367763926166363648, 355088403981918272, 358140732212706304, 
342823915606135936), SA2 = c(4.06998e+15, 4.05015e+15, 3.94057e+15, 
3.9507e+15, 3.58963e+15, 3.53037e+15, 3.43302e+15, 3.20139e+15, 
3.94638e+15, 3.03403e+15, 3.15862e+15)), row.names = c(NA, -11L
), class = "data.frame")
test$SA=as.numeric(levels(test$SA))[test$SA]
test$SA1=as.numeric(levels(test$SA1))[test$SA1]
test$SA2=as.numeric(levels(test$SA2))[test$SA2]
ggplot(test,aes(x=year, y=  SA, group = 1)) + geom_line(mapping = aes(x = test$year, y = test$SA)) +
  geom_line(mapping = aes(x = test$year,y = test$SA2), color = "red")+ geom_line(mapping = aes(x = test$year, y = test$SA1/100), + geom_smooth(method = "lm")
      size = 1, color = "blue")+ scale_y_continuous(name = " Primary axis", sec.axis = sec_axis(~.*100, name = "Secondary axis"))

i also tried reshaping the data and then plot the trend lines for 3 variables but secondary axis got detoriated.

df <- reshape2::melt(test, id.var = "year")
df
   year variable        value
1  2008       SA 1.409155e+15
2  2009       SA 1.533598e+15
3  2010       SA1 1.524728e+15
4  2011       SA1 1.583941e+15
..
..
5  2017       SA2 1.597022e+15
6  2018       SA2 1.549362e+15

ggplot(df,aes(x=year, y=  value, group = variable)) + geom_line()+ scale_y_continuous(name = "y axis", sec.axis = sec_axis(~.*100, name = "y axis"))+ geom_smooth(method = "lm")

Using the code provided by @Rui Barradas - Reinstate Monic: i got the following plot

library(dplyr)
library(tidyr)
library(ggplot2)

test %>%
  mutate(SA1 = SA1/100) %>%
  gather(sa, value, -year) %>%
  ggplot(aes(x = year, y = value, group = sa, colour = sa)) +
  geom_line() +
  geom_smooth(method = "lm", formula = y ~ x) +
  scale_color_manual(values = c("black", "red", "blue")) +
  scale_y_continuous(name = " Primary axis", sec.axis = sec_axis(~.*100, name = "Secondary axis"))

Solution

This sort of problem is usually a data reformating problem. See reshaping data.frame from wide to long format.
And with the data as posted there is no need to coerce columns SA, SA1 and SA2 to numeric, they were not posted as factors.

library(dplyr)
library(tidyr)
library(ggplot2)

test %>%
  mutate(SA1 = SA1/100) %>%
  gather(sa, value, -year) %>%
  ggplot(aes(x = year, y = value, group = sa, colour = sa)) +
  geom_line() +
  geom_smooth(method = "lm", formula = y ~ x) +
  scale_color_manual(values = c("black", "red", "blue")) +
  scale_y_continuous(name = " Primary axis", sec.axis = sec_axis(~.*100, name = "Secondary axis"))