What is the general trend of trade barriers over recent decades: higher, lower, or about the same?

Trade barriers refer to restricting the exchange of goods and services through imports and exports by imposing tariffs, quotas, non-tariff barriers, taxes, etc.

Trend in these trade barriers refer to that how in the past few decades the countries have reacted to free trade- i.e. whether they are restricting the free trade, promoting it, or maintaining the same outlook as before.

Generally speaking, the trade barriers over the past six decades or so have been lowered down by countries across the globe, implying a promotion of free trade policies. The countries are now more globalized, closer to each other than ever, and the distance shall only drop virtually in the times to come.

Though violations of trading norms and barriers are reported often, but the world has only accepted free trade between the countries now, than ever before.