In the U.S.A., some activities are seeing more participants and others are seeing fewer, however, the overall trend has been upward. That is projected to continue. The short answer = up. More info:

In the period from 1999–2009, the declining categories were:

• mountain climbing (-5.9%)
• snowmobiling (-5.5%)
• migratory bird hunting (-1.1%)
• downhill skiing (-8.5%)
• cross country skiing (-21.7%)
• snowshoeing (-9.4%)
• scuba diving (-5.6%)
• wind surfing (-10.1%)
• rafting (- 2.8%)

All other categories increased.

In projections to 2030, all categories increase except when climate change is factoring in. In that case motorized snow use and undeveloped skiing decline.

All of this comes from a U.S. Forest Service study published last November (2016). The report has much more detail. Get those details at: https://www.fs.fed.us/pnw/pubs/pnw_gtr945.pdf