[O] hlines in babel output

[Rasmus]

Hi,

I have the following Org document where I would like to add some extra
hlines to the output.  I'm using babel.  I tried the ascii package but
couldn't find anything giving me extra hlines.  I'd also prefer to
stick to just babel. 

Here's the example:

#+begin_src org

#+TITLE:hline test
* Some R code
I have the following R code and I want to add hlines to the final
output since it is exported and needs to look good.  In particular,
it is desired that the last line is separated with an hline. 

I could do it by exporting directly to LaTeX, but I would rather
export to an Org table.

#+NAME:budget-dta
#+begin_src R  :colnames yes
  tt <- textConnection("
  account     p
  rent        110
  food        50")
  ee <- read.table(tt, header = TRUE)
  close(tt)
  cc <- 4 ## a complicated number generated with R
  
  ee$p <- ee$p * cc
  
  ee <- rbind(ee, data.frame(p=sum(ee$p),account=c("total")))
  ee 
#+end_src

* Actual output:
#+RESULTS: budget-dta
| account |   p |
|---------+-----|
| rent    | 440 |
| food    | 200 |
| total   | 640 |

* Minimally desired output
| account |   p |
|---------+-----|
| rent    | 440 |
| food    | 200 |
|---------+-----|
| total   | 640 |

* Most desired output
|---------+-----|
| account |   p |
|---------+-----|
| rent    | 440 |
| food    | 200 |
|---------+-----|
| total   | 640 |
|---------+-----|

#+end_src


-- 
. . . The proofs are technical in nature and provides no real understanding.