It certainly has been a great year for Aussie investors.

The S&P/ASX 200 Index (ASX: XJO) has had a number of ups and down since 1 January, but the ups are leading the way and making Australia richer.

In fact, the ASX 200 index hit a record high of 8,331.7 points on Tuesday before closing a touch below that at 8,252.8 points.

But what sort of return would I have got if I had invested in the index at the start of the year? Let's find out what a $20,000 investment would be worth today.

$20,000 invested into the ASX 200

Firstly, unless I buy all 200 shares that feature in the benchmark index, I can't actually invest directly in the ASX 200.

However, there are exchange traded funds (ETFs) out there that will allow you to mimic this, but with small fees.

One of those is the iShares Core S&P/ASX 200 ETF (ASX: IOZ). The fund manager, Blackrock, notes that this ETF aims to provide investors with the performance of the S&P/ASX 200 Accumulation Index, before fees and expenses. This index is designed to measure the performance of the 200 largest Australian securities listed on the ASX.

The returns

Let's assume that I put $20,000 into the iShares Core S&P/ASX 200 ETF just before the close of play on 29 December (the last trading day of 2023).

At that point, I could have picked up units for $30.71 each. This means that with a $20,000 investment (and an extra $22.92 for good measure), I would have ended up owning 652 units.

On Tuesday, the iShares Core S&P/ASX 200 ETF ended the session at $33.43. This means that my 652 units would now have a market value of $21,796.36. That's $1,773.44 more than I started with and represents a return of approximately 8.9%.

But that's not where the returns stop. The ASX 200 index is home to a large number of dividend payers.

Much like if I had invested in all 200 shares on the index, I am entitled to my share of these dividends by owning this ETF.

Since the start of the year, the ETF has paid three dividends, with a fourth on the way next week. These dividends total $1.1448 per share, which means that my 652 units would have pulled in an extra $746.41 in dividend income.

Combined with my share price gains, that is a total return of $2,519.85 from my $20,000 investment. And there's still two and a half months to come.