Passive Income-to-Equity Ratio

[Cole Melcher]

After re-reading Rich Dad's Cashflow Quadrant, I have a renewed focus of increasing our passive income from our investments. Up to this point, my main focus has been on increasing our net worth. 

Right now we are generating a cashflow of 3.4% on the equity we have in our rentals. That is after subtracting a 10% vacancy rate and a generous estimate of maintenance expenses. 3.4% seems very low to me, however, I have searched the internet and cannot find any discussions on passive income returns on equity. What are other people seeing on their rentals?