It depends on many factors: how much you initially paid, what the interest rate is, and how much it is actually worth. For instance: If you paid $100, and you get $2 every six months, and it's worth $90, it is worth $166.
That would depend on the maturity value and the bond series. Some bonds gain intrest until the maturity date and then they are worth their face value. Some bonds continue to gain intrest until they are cashed in. Your bond may still be gaining value.
The easiest way to determine what 19 year old savings bonds are worth is to go to one of the many federal saving bond sites and plug in the dates of the bonds. Once the dates are inserted into the web site the interest amount will calculated for you.