Retirement Planning Purposes
The numbers you should use for Retirement Planning Purposes is real % total yield is net of inflation. So a 5% total yield with 3% inflation would be a 2% real % yield.
When you are looking for investments for Retirement Planning Purposes with judicious investments in equities, you should expect long term returns of 6% conservatively. That is based on historical trends. Many good mutual funds have returned better than that. Some as much as 16% for long periods of time. But I doubt that in the future that will be the case unless one looks to overseas and developing markets. Some of those however can hardly be considered conservative. A mixed portfolio of 30-40% debt and 60-70% equities is considered more conservative than one of 100% equities. Interestingly enough, studies have shown that such a portfolio will outperform a portfolio of all equities over a long period of time with reduced risk.
That of course is all based on historical data. That data might not be appropriate for future investment returns for Retirement Planning Purposes.