Look here and make your own guess: https://productioncommunity.publicmobile.ca/t5/kudos/kudosleaderboardpage/category-id/Public_Mobile_...
BUT be aware Bravos are only part of the secret (from us) calculation.
From everyone's experience...how many posts/bravos are needed to be in the top 50%?
Your community rewards are based on a combination of your total participation statistics, including topics started, replies made, bravos received, bravos given, solutions authored, solutions marked accepted, lab ideas submitted, etc. Only PM knows the formula by which all of these stats are combined. There's no exact number of each stat required for any particular level, as that can change each month according to overall activity levels in the community. From what I've seen, it really doesn't take much to make it to the top 50%. Basically, anyone who makes any reasonable effort to participate should manage to achieve some level of reward.