[R] Looking for help in calculating percentiles

[arinbasu@softhome.net]

Hi All: 

I am working with a dataset on Arsenic toxicity, and I am trying to 
calculate the 20th, 40th, 60th, 80th, and highest percentiles for a 
variable, dietary Moisture (variable name dMoist). 

The inbuilt function quantile(dMoist) would print 0, 25th, 50th, 75th, and 
100th percentile. Does there exist a function that can calculate xth 
percentile (where x = 10th, 20th, ... etc) values? 

I looked for such functions in the documentation, but couldn't find one. Has 
anyone written a similar function that can be used? Is there a module or a 
function that I have missed? 

I use R in both Windows XP as well as Linux (Fedora Core 1 (Yarrow)) on a 
Duron I Gz machine with 128 MB RAM. 

Thanks in Advance,
Arin Basu