Would you and xfile put some dates on those percentage numbers?
Without a timeframe, the percentages become meaningless.

Mine was based on memory of reading a very recent report which is around
28%-29%,but I don't have it with me.

But it's easy to find other numbers, such as reported by Netmarketshare,
which has a even higher percentage: 31.22%
(http://netmarketshare.com/operating-...0&qpcustomd=0).

IDC also released a press release for general public titled: IDC
Forecasts PC Shipments to Fall by Double Digits In 2013; Volumes Are
Expected To Stabilize Above 300 Million Units per Year, But With No
Significant Recovery

(http://www.idc.com/getdoc.jsp?containerId=prUS24466513)


Excerpt:

"The commercial market is faring notably better than the consumer market
in 2013 with shipments declining by -5% year over year compared to
nearly -15% for consumer."

"The relative stability is due to a mix of more stable PC investment
planning, a smaller impact from tablets, and to replacements of Windows
XP systems before the end of support planned for 2014."

"However, the long-term outlook for the two markets is not significantly
different, with a small decline projected for both consumer and
commercial segments in 2014 with near flat growth in the longer term."

Edit: Replacement of XP from business will help but "the long-term
outlook for the two markets is not significantly different, [...]".

Excerpt:

"Perhaps the chief concern for future PC demand is a lack of reasons to
replace an older system," said Jay Chou, Senior Research Analyst,
Worldwide Quarterly PC Trackers at IDC."

Edit: This is what is called "diminishing return" that I mentioned,
which means that there is little or no benefits for additional
investments including for replacements, and it has been like this for
some time.