Angular Form Control valueChanges not working

I want to get one of my forms ("family") value if changed by subscribe but it seems something wrong, because I got nothing on my console's log.

import { Component , AfterViewInit } from '@angular/core';
import {FormGroup,FormBuilder} from '@angular/forms';
import {Observable} from 'rxjs/Rx';

@Component({
selector: 'app-root',
template: `<h1>Hello World!</h1>
            <form [formGroup]="frm1">
            <input type="text" formControlName="name" >
            <input type="text" formControlName="family">
            </form>
            `,

})

export class AppComponent implements AfterViewInit{ 

 frm1 : FormGroup;

constructor( fb:FormBuilder){
    this.frm1 = fb.group({
        name : [],
        family: []
    });     
}
ngAfterViewInit(){  
    var search = this.frm1.controls.family;
    search.valueChanges.subscribe( x => console.log(x));    
}
}