Question : VLANs in Cisco Switches

I have 20 Cisco Switches in a building who are feeding network to 250 users on 4 floors and 6 depts . All Users are operating in a sigle vlan which is 1 . just plug and play .

My question here is i need to  convince my manager to implement VLANS in this network to improve effieceny and network utilization , but the problem is he is not a teche , all he wants the less complexicity and less maintenance and thats why he says keep it running how it is .

how i can make him believe that implementing VLANS will significatnly improve network browing speed and improve the response time if i have to show him as data copy from PC to PC . or internal web applications and shared folders access which are as shared storage within a LAN

Answer : VLANs in Cisco Switches

VLAN 1 can't be the only thing going on (or the sh ip stat wasn't the same time period):
VLAN 1: 6702101 packets Input & 1101 packets output = 6703202
IP Traffic: Rcvd:  49529506 total & Sent:  265670 generated = 49795176

VLAN 1 is only 13.4% of the IP traffic? (Check my math, and that I'm comparing like statistics)