**Better than original?**

How many are left?, that is a good question, along with how many were actually produced?

Of course how many GTA replicas have been made? or will be made in the future? are complementary questions (okay fair enough not the question asked UlrichGTA)

Here are some thoughts to answering the question as narrowed down by Ken who asked is it possible to estimate the current population size (number left) of LHD GTAs using the estimate of the population size (number left) of the RHD GTAs.

Or was Ken asking can you use the RHD GTA sample data to work out the sample estimates of the actual population characteristics of total GTAs like destruction rates of the population of all GTAs, thus LHD GTAs?

You could argue they are two different populations LHD and RHD and they have some things in common, like decay rates or destruction over time. Or that they are one population of GTAs and we can use the RHD GTA data to work out estimates of the population of GTAs

Statistically you would first be trying to use an estimate of the decay rate (destruction over time) of RHD GTAs cars over time which gives you a point in 2017 with the final population estimate (number) of RHD GTAs and use the RHD GTA decay rate as an estimate of the decay rate of the total GTAs to give a final estimate of LHD GTAs in 2017.

Some of the know variables/constants are starting population numbers?, others unknown variables are reliability of cars and drivers skills and tracks and their conditions and other race cars etc.

If the variables that are used to describe the decay rate (over time) are the same for both then you may be able to estimate the number of LHD GTAs left.

In my opinion the variables would be too hard to estimate as there would be missing information and you would have to make subjective calls on drivers ability /ranking and track conditions and team vs private car preparation, tyre choices and the RHD GTAs participated in different races in different countries as to the LHD cars etc..

Another approach is to draw a time line of cars destruction.

The 50 RHD GTAs time zero let's say eg. after the first year X destroyed cars, produce a graph of all the RHD GTA cars for each year from 1965 year. On the vertical (Y) axis put the number of cars still remaining on the horizontal axis put the year.

Since not all cars were built at the same time, you have to consider the build rate adding of cars over time combining with the destruction of cars over time to give population size for each year, thus the decay 'destruction over time'.

Of course the decay rates of RHD and LHD cars may be the same if they are part of the same population and you can use the RHD GTA data as an estimate.

In the end you may just have to plot the LHD GTA decay rate and compare with the more complete data from the RHD GTA decay rate.

If the decay rates are very different then I would suggest they are two different populations thus survival rates will be different, so doing a simple percentage ratio of RHD to LHD may not work.

Cheers Steve