Heavy swap usage on EBS Apps Server

Dear All,

We have two servers - one for Database and other for Apps Server.

When we bounced the applications processes, it shows no swapping for first few days.

However, swapping starts and increases as time passes by.

We have Red Had Linux 5.4 and 13G physical memory along with 16G swap space for apps server and same OS 40G physical memory along with 16G swap space for DB server.
$ free -m

             total       used       free     shared    buffers     cached

Mem:         13913      13771        141          0        302       1604

-/+ buffers/cache:      11864       2049

Swap:        16386       4956      11429

sar gives:

$ sar -r 5 5
Linux 2.6.18-164.el5 (oraapp01.fti-nbil.com)    12/07/2015

10:16:18 AM kbmemfree kbmemused  %memused kbbuffers  kbcached kbswpfree kbswpused  %swpused  kbswpcad