angular onchange event

import { Component } from '@angular/core';

@Component({
  selector: 'my-app',
  template: `
    <input type="number" [ngModel]="percent" (ngModelChange)="onPercentChange($event)" />
  `,
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  percent = 20;

  onPercentChange(percent: number) {
    console.log('here');  

    this.percent = percent;
  }
}
<select class='select-option'
    #mySelect
    (change)='onOptionsSelected(mySelect.value)'>
   <option class='option' 
   *ngFor='let option of dropDownData' 
   [value]="option.seo_val">{{option.text_val}}</option>
</select>