Read the passage below and solve the questions based on it.
There are two brands of TV, Onida and Videocon, in the market. Onida is an old brand launched in 1990 and Videocon is a new brand launched in 1997. For both these brands, 30% of the TV’s purchased every year are disposed off as out-dated exactly two years later. It is known that 10 Onida TV’s were disposed off in 1997. The following table gives us the number of TV’s in operation at the end of the year from 1995 to 2000.
What is the average number of Onida TVs purchased every year till 1995?