As a function of time, is this a linear trend or non linear trend?

04/08/19 04/16/19 04/24/19 05/02/19 05/10/19 05/18/19 05/26/19 06/03/19 06/11/19 06/19/19 06/27/19 07/05/19 07/13/19 07/21/19 07/29/19 08/06/19 08/14/19 08/22/19 08/30/19 Chart Area 09/07/19 09/15/19 09/23/19 10/01/19 10/09/19 10/17/19 10/25/19 11/02/19 11/10/19 11/18/19 11/26/19 12/04/19 12/12/19 12/20/19 12/28/19 01/05/20 01/13/20 01/21/20 01/29/20 02/06/20 02/14/20 02/22/20 03/01/20 03/09/20 03/17/20 03/25/20 04/02/20 -20 -15 -10 -5 0 5 10 15 20 Returns