Hallo,
         Normal Blood Pressure is 120 / 80.  This is suggested Range.
    140 / 90 is High Normal. Above this range , is called 
High Blood Pressure.
But you are not mentioned your age and the time of mesurement, either  in the morning or  evening ,either before food or after food.
     Any way your Blood Pressure Range is 136 / 88 ,according to your statement.
     Now it is High Normal , eventhough it is possible to increase in future,
   So that,say good bye to High salt foods , 
Saturated Fat , Hydrogenated Oils and Vegetable Oils.
   Add , Apples, Bananas , Grapes , Orange juice and plenty of 
Cold water.
           Keep good health.