There are some problems with your data, you are using non syntactic column names (this could bring you problems in the future) and you have numeric variables stored as text. Also, you are not telling us what is the specific formula for the variable you want to create but this is an example that you could easily adapt to your actual application.
library(tidyverse)
# Sample data
d1 <- tibble::tribble(
~Country, ~'Population.(people):', ~'Population.(%):', ~'Total.GDP.(million.euro)', ~'Total.GDP.(%)', ~'Number.of.past.applications.(number):', ~'Number.of.past.applications.(%):', ~'Unemployment.rate.(%.of.active.population)',
"Austria", "8 822 267", "1,68 %", 1127, "3,24 %", "196 875", "4,15 %", 49,
"Belgium", "11 398 589", "2,16 %", 1083, "3,11 %", "126 520", "2,66 %", 6,
"Bulgaria", "7 050 034", "1,34 %", 1029, "2,96 %", "57 120", "1,20 %", 52,
"Croatia", "4 105 493", "0,78 %", 1005, "2,89 %", "4 660", "0,10 %", 84,
"Cyprus", "864 236", "0,16 %", 1034, "2,97 %", "19 315", "0,41 %", 84
)
# Replace non syntactic names
names(d1) <- c("Country", "Population", "Population_pct", "Total_GDP", "Total_GDP_pct", "Past_applications", "Past_applications_pct", "Unemployment")
d1 %>%
mutate(Population = parse_number(Population), # Convert text into numeric values
Past_applications = parse_number(Past_applications), # Convert text into numeric values
Key = Population * 0.4 + Total_GDP * 0.4 + Past_applications * 0.1 + Unemployment * 0.1) %>%
select(Country, Key)
#> # A tibble: 5 x 2
#> Country Key
#> <chr> <dbl>
#> 1 Austria 478.
#> 2 Belgium 451.
#> 3 Bulgaria 425.
#> 4 Croatia 412.
#> 5 Cyprus 770.
Created on 2019-08-14 by the reprex package (v0.3.0.9000)