It's a great question. Look, Patrick, let's just take a full step back on Waters, right? As you know and many on the call know, we've grown instruments roughly 5%. And I know your question is targeted towards instruments. Instruments have grown on average 5% over the last 15 years, right? And those statistics are sort of easily available given that we've not done a lot of M&A. You can look at our longitudinal history on instruments, right? So about 5% on average, but no year is actually 5% on the dot, right? There are 5 that are well below 5 that are well above and 5 close to the average, right?
So you start with that. And since I've been at the company in the last 3.5 years, we've seen a microcosm of that already, right? So 2 years of 20-plus percent growth and now a bit of decline in instrument growth rate. We didn't get too excited when things were at 20-plus percent growth for several quarters in a row. And we said this is not going to last just given the long-term averages. And we're not so phased when we look at what we are seeing now. And now let me sort of address your question just with that as context, it's very difficult to predict a quarter-on-quarter rollout of instruments for Waters.
But I think it's more instructive to look at the 5-year average, especially when you think about LC. And a 5-year CAGR for LC is operating now at the low single-digit level. In China, it's almost double-digit decline. So we are due for a replacement cycle to begin very soon in LC instrumentation. And remember, these are used in QA/QC. So you can't forever defer these replacements. And the conversations that we've had with customers, and as I said, I spent a whole day with one of our largest customers, especially in QA/QC, they are raring to go and start the replacement cycles, right, on LCs.
The aging fleet is not something that they want to have, especially for new launches, which are going to be high volume and, of course, marketed compounds. So I think things are trending in the right direction. But again, I mean, just put this all in context, there's really, again, one shouldn't get too excited when you see high growth and decline, especially for our instrument portfolio. And when you look at the full year, again, I'll remind you that it's a 45, 55 average for the overall business, right?
First half, 45%, second half, 55%, and that's what we've assumed for the full year phasing overall, and the step-up in the second quarter is roughly 10%. So just sort of give you broad sort of signpost. But the conversations were with a QA -- with a heavy focus on QA/QC. And we see replacement -- signs of replacement cycles beginning both in China, which we commented on earlier, ex-China.