> In return for her money, the water board promised Jorisdochter, her descendants or anyone who owned the bearer bond 2.5 per cent interest in perpetuity.
This is inaccurate; it was 5%:
> According to its original terms, the bond would pay 5% interest in perpetuity, although the interest rate was reduced to 3.5% and then 2.5% during the 18th century. [1]
Sounds like the Wikipedia article is talking about a different set of bonds, "Another of these bonds, issued in 1648, is currently in the possession of Yale University."
From the article, it looks like the original interest on this one was 6.25% (75/1200) though.
This is inaccurate; it was 5%:
> According to its original terms, the bond would pay 5% interest in perpetuity, although the interest rate was reduced to 3.5% and then 2.5% during the 18th century. [1]
[1]: https://en.wikipedia.org/wiki/Perpetual_bond