length of map golang

package main
 
import "fmt"
 
func main() {
    var employee = make(map[string]int)
    employee["Mark"] = 10
    employee["Sandy"] = 20
 
    // Empty Map
    employeeList := make(map[string]int)
 
    fmt.Println(len(employee))     // 2
    fmt.Println(len(employeeList)) // 0
}