Hello! I am trying to calculate percentage change of Real GDP per capita in R. However, I get Error: non-numeric argument to binary operator. By the way, this is the first question I ever submit, so please excuse me if I mess up the information needed.

The data set contains GDP and HCIP for the EU, Norway, Sweden, and Denmark from 1995 - 2020.

```
library(readxl)
data <- read_excel("dataEUNORD.xlsx")
# Real GDP
EURY <- 100*data$`YP - Euro area*`/data$`HCIP - Euro area*`
NORY <- 100*data$`YP - Norway`/data$`HCIP - Norway`
DKRY <- 100*data$`YP - Denmark`/data$`HCIP - Denmark`
SERY <- 100*data$`YP - Sweden`/data$`HCIP - Sweden`
# Making a set of all 4 real GDPs (include the year)
RY <- cbind(data[,1], EURY, NORY, DKRY, SERY)
# Taking the log differences as percentage change
growth <- 100*diff(log(RY))
```

Error in r[i1] - r[-length(r):-(length(r) - lag + 1L)] :

non-numeric argument to binary operator

Trying to solve it, i have usind these codes, however, I am still not able to produce a growth rate:

```
RY2 = as.data.frame(sapply(RY, as.numeric))
RY3 = as.numeric(RY)
growth <- 100*diff(as.numeric(log(RY)))
growth <- 100*diff(log(RY2))
growth <- 100*diff(log(RY3))
```

Error: 'list' object cannot be coerced to type 'double'

I hope this is enough information so you'll be able to help. In any case, thank you very much in advance!