Is it true that 20% of church members do 80% of the work? It appears that this is true with many congregations.   And, of course, there are exceptions.   I have personally worked and worshipped with congregations where 40% to 80% of the members were involved in some sort of ministry in the local church.   I have also been told by church leaders that only about 10% of their congregation were involved in ministry.
This generalization possibly needs to be reworded thusly:
20% of a church’s membership does 100% of the work.
I’m going to suggest that someone (the church secretary, an elder, the preacher) in every congregation take out the church directory and go page by page and determine which members are doing anything (in the way of ministry) for the local church other than attending and contributing money.   
You can get the percentage by dividing the number of involved members by the number of members you have.  For example, if you have 150 members and only 30 of them do anything in the way of ministry, you divide 30 by 150 and you will get .2 or 20%.
Having done the math, how do we increase the 20%?
If you have invested the time to discover not only the percentage of members involved in ministry in your congregation BUT also WHO IS NOT INVOLVED, you will probably experience a bit of shock and want to know how to INCREASE the percentage.   May I suggest the following 3 things: Decide to make the changes necessary to increase the percentage.  Start educating the brethren on what the Bible teaches about ministryUse the tools that equip and prepare the brethren to serve. 
It just so happens that I have tools, knowledge and experience to assist you in getting you started in this adventure.
There are 3 ways to approach your needs:
Retreats are one-day presentations (usually six hours) which are not only fun but will assist church leaders in determining if they wish to invest more in starting an effective involvement ministry.
Workshops are nine hours of intense training for church leaders, deacons and church staff.   Workshops are only for congregations that are serious about getting members involved in ministry.
Residencies are for congregations who have made the decision to move ahead and start an involvement ministry.   Residencies consist any time period from one to thirteen weeks of my residing and working with a congregation.   Residencies are optional.
Travis Irwin
2134 River Chase Drive
Murfreesboro, TN 37128
423 920 3060
You you can find free videoes on facebook:
My facebook group:   Church Involvement Ministers
                   Church Involvement Dot Com