Memory configuration for vCneter server

Hi,

Here is current environment.

• vCenter Server, vCenter Single Sign On and vCenter Inventory Service running on same server
• 9 Hosts (2 clusters. one for 5 hosts, one for 6 hosts)
• 100 - 120 VMs

- My vCenter server has 16GB memory but over 90% is using.

- SQL server memory (Min 8GB, max 14GB)

- vCenter Inventory Service in wrapper.conf (6144 MB)

- VirtualCenter Management WebServices in wrapper.conf (-Xmx2048M)

- vSphere Profile-Driven Storage in wrapper.conf (2048 MB)

How can I decrease memoey utilization for vCenter ??