There are two companies X and Y, each having three groups: HR, Marketing, and Finance. The details are as follows: Company X has 64 existing members d...

There are two companies X and Y, each having three groups: HR, Marketing, and Finance. The details are as follows:

• Company X has 64 existing members distributed among the groups. When 2 new members are added to each group, the ratio of total members in HR and Marketing combined to Finance becomes $4 : 3$.
• Company Y has 6 existing members in HR (no new members added here) and 10 existing members in Finance.
• Additional information:
  1. Total members (new + existing) in Finance group of company Y is half of the total members (new + existing) in Marketing group of company X.
  2. New members added in Finance group of company Y are half the number of new members added in Marketing group of company Y.
  3. Total members (new + existing) in Marketing group of company X exceed those in Marketing group of company Y by 6.
  4. Total members (new + existing) in HR group of company X and Finance group of company Y sum to 28.

Using this information, calculate approximately by what percentage the total existing members in HR and Marketing groups of both companies exceed the total members (new + existing) in company Y.