List a count of the number of vendors each inventory item was purchased from over the last 180 days. With the assumption that inventory purchases are spread out among vendors evenly, this helps identify items where the number of vendors purchased from is too low potentially indicating favoring certain vendors.

Vendor Vendor ID VendorName Vendor Address 1 Vendor Address2 Vendor City Wendorstate Vendor Zip ContactName VendorphoneNumber Employee Employee Name Employee Address EmployeeCity Employee State Employeezip EmployeePhoneNumber purchaseOrder Date ExpectedDeliveryDat Vendor ID Buyer ID Inventory Inventory Name PurchaseOrder Inventory Inventory umber Purchase Order Quantity Purchase OrderUnitPrice