Incorrect reporting of Linux O/S

I found that the memory reporting for the system I am using is always 6% ... and I have access the "vmstat -s" and "top" command from the linux system, the actual correct % should 48% if calculate by total memory (virtual + physical) .. or 96% if calculate by just the physical memory (physical only) ..

May I know what's wrong? and how should i have the tools to report it correctly?

Below is the information from my Linux "dmesg" for your reference.
Linux version 2.6.9-42.0.10.ELsmp (mockbuild@builder7.centos.org) (gcc version 3
.4.6 20060404 (Red Hat 3.4.6-3)) #1 SMP Tue Feb 27 10:11:19 EST 2007
BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 000000000009ac00 (usable)
BIOS-e820: 000000000009ac00 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 00000000bffcb600 (usable)
BIOS-e820: 00000000bffcb600 - 00000000bffceac0 (ACPI data)
BIOS-e820: 00000000bffceac0 - 00000000c0000000 (reserved)
BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved)
BIOS-e820: 0000000100000000 - 00000001c0000000 (usable)
6272MB HIGHMEM available.
896MB LOWMEM available.
.
.
.

Information from "vmstat -s"
6227912 total memory
6002368 used memory
5141020 active memory
775664 inactive memory
225544 free memory
108316 buffer memory
5502084 swap cache
6144852 total swap
144 used swap
6144708 free swap

Kok K-L