Keep in mind that some audiences will not laugh at everything you think is funny and other audiences will laugh at things you didn't think were funny. You might just surprise yourself and discover you are funnier than you imagined. Your laugh ratio might demonstrate that you already have as many laughs as you desire. Go forth, speak, and worry no more about the humor in your speeches. Speakers often make the mistake of judging their humor content by looking solely for obviously humorous-type lines in their talks.
Audiences laugh at much more than just obviously funny lines.
They laugh at undisguised passion, recognition of concepts that are a part of their own experiences, the juxtaposition of two sentences that together convey some synergistic humorous thought, and many other non-joke elements. Often a laugh is brought forth simply by pausing and giving the audience time to recognize the humor. In other cases, it is simply a matter of some minor restructuring, rewriting, or repositioning a line differently for maximum effectiveness. This, by and large, is a fairly straightforward matter and for the most part doesn't take hours of time. Nor does it usually involve any radical restructuring of your talk or adding a bunch of 'jokes'.