How rare is it to find Neptune's Glaive and a Broken Trident while fishing?

I've been playing some Stardew Valley and I was fishing since its a lucky day. I got a fishing treasure chest with both a Neptune's Glaive and a Broken Trident in it. I'm just wondering how rare it is to have gotten both of these items in one chest. On the wiki it says they both have a 0.7% chance of being found in a fishing treasure chest separately. I don't have any accessories or skills that increases the chance of rare items / treasure chests being found whilst fishing, unless the normal fishing bait and a fiberglass rod changes the chances. (I'm just on the latest version)